)phosphonate; Application of Olefin Cross Metathesischempublishers.com/wp-content/uploads/2019/04/edited_5_3_Paper_4.pdfOlefin metathesis has become a mainstay in organic synthesis4,5

Full Paper

ISSN (Print): 2220-2625

ISSN (Online): 2222-307X

*Corresponding Author Received 20th

August 2013, Accepted 23rd

January 2015

Synthesis and Characterization of Novel (E)-tert-butyl 7-(4-methoxyphenyl)-5-(4,4,5,5-

tetramethyl-1,3,2-dioxaborolan-2-yl)hept-2-enoate and (E)-diethyl (6-(4-

methoxyphenyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hex-1-en-1-

yl)phosphonate; Application of Olefin Cross Metathesis

*H. Hussain, S. R. Gilani, Z. Ali and I. Hussain

Department of Chemistry, University of Engineering and Technology, Lahore, Pakistan

Email: *[email protected]

ABSTRACT Two novel compounds (E)-tert-butyl 7-(4-methoxyphenyl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hept-2-enoate and (E)-

diethyl (6-(4-methoxyphenyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hex-1-en-1-yl)phosphonate were synthesized in

excellent yields by olefin cross metathesis (CM). 3-(4-methoxyphenyl)propyl diisopropylcarbamate and allylboronic acid pinacol

ester were reacted in the presence of s-BuLi/N,N,N,N-tetramethylethyllenediamine (TMEDA) to form sec. boronic ester which

was further reacted with tert-butyl acrylate and diethyl vinylphosphonate respectively to get the desired products. Both novel

compounds have applications as reactants for cyclopropanation and cyclopentataion for asymmetric synthesis.

Keywords: Allylic boronic ester, Lithiation Borylation, Olefin Cross Metathesis, Hoveyda-Grubbs Catalyst 2nd Generation,

Asymmetric synthesis.

1. INTRODUCTION The formation of carbon-carbon double bonds by olefin metathesis is the most powerful and broadly applicable

synthetic tool of modern organic chemistry1-3

. Olefin metathesis has become a mainstay in organic synthesis4,5

that is

becoming an increasingly important tool in the synthesis of small molecules, preparation of natural products, and

construction of polymers. It is a metal-catalyzed transformation, which acts on carbon carbon double bonds and

rearranges them via cleavage and reassembly6,7

. According to this mechanism, first introduced by Chauvin, the

coordination of an olefin to a metal carbene catalytic species leads to the reversible formation of a metallacyclobutane.

This intermediate then proceeds by cycloreversion via either of the two possible paths: 1) non-productive—resulting

in the re-formation of the starting materials or 2) product-forming—yielding an olefin that has exchanged a carbon

with the catalyst’s alkylidene. Since all of these processes are fully reversible only statistical mixtures of starting

materials as well as all of possible rearrangement products are produced in the absence of thermodynamic driving

forces8. This method is especially effective in the case of cross metathesis (CM) reactions involving terminal olefins

9.

In particular, cross metathesis (CM) reactions promoted by ruthenium-based catalysts have been widely utilized by

synthetic organic as well as polymer chemists in the construction of higher olefins from simple alkene precursors10

. N-

Heterocyclic carbene (NHC) ligand-containing catalysts, such as the second-generation Grubbs catalyst

11 are widely

used. Karl Voigtritter12

studied iodide effect on olefin cross metathesis reactions. Many attempts had been made for

cyclopropanation and cyclopentanation reactions using boron-ate complexes. A number of boronic esters were tried

for cyclopropanation and cyclopentanation. Abbasi13

synthesized different sulfonamides including heterocyclic

moieties for the evaluation of their various biological activities.

In this study, we synthesized such boronic esters which have electron withdrawing groups by carrying out CM

reactions used. These compounds might be used as starting materials for asymmetric synthesis if electron withdrawing

groups could promote cyclopropanation and cyclopentanation. It was expected that the presence of electron

withdrawing groups on boronic esters definitely promote 1, 3-migration to cyclopropanation and cyclopentanation.

Allylic boronic ester (3) was first synthesized by the reaction of 3-(4-methoxyphenyl)propyl diisopropylcarbamate (1)

with allylboronic acid pinacol ester (2). Allylic boronic ester (3) was the reacted with tert-butyl acrylate (4) and

diethyl vinylphosphonate (6) to synthesize novel compounds (E)-tert-butyl 7-(4-methoxyphenyl)-5-(4,4,5,5-

tetramethyl-1,3,2-dioxaborolan-2-yl)hept-2-enoate (5) and (E)-diethyl (6-(4-methoxyphenyl)-4-(4,4,5,5-tetramethyl-

1,3,2-dioxaborolan-2-yl)hex-1-en-1-yl)phosphonate (7).

2. EXPERIMENTAL SECTION

2.1 Materials Sec. butyllithium solution (sBuLi) (1.6M), allylboronic acid pinacol ester, N,N,N,N-tetramethylethyllenediamine

(TMEDA), diethyl vinylphosphonate and Hoveyda-Grubbs Catalyst 2nd Generation were purchased form Sigma

Aldrich and tert-butyl acrylate was taken from Acros. All chemicals were used as such as received. TMEDA was

distilled over CaH2. Anhydrous diethyl ether (Et2O) and dichloromethane (DCM) were obtained under nitrogen

andstored in Young’s flasks over 4Ao molecular sieves. Reaction was carried out in flame-dried glassware under

nitrogen atmosphere.

Pak. J. Chem. 5(3): 117-125, 2015

DOI:10.15228/2015.v05.i03.p04

Pakistan Journal of Chemistry 2015

2.2 Synthesis and Characterization of 2-(1-(4-methoxyphenyl)hex-5-en-3-yl)-4,4,5,5-tetramethyl-1,3,2-

dioxaborolane (3) To a solution of 3-(4-methoxyphenyl)propyl diisopropylcarbamate (1.0g, 3.41mmol, 1.0eq) (1) and N,N,N,N-

tetramethylethyllenediamine (TMEDA) (0.61mL, 4.09mmol, 1.2eq) (2a) in Et2O (17mL) at -78oC was added Sec.

BuLi (1.6M in 92:8 cyclohexane/hexane, 2.9mL, 3.75mmol, 1.1eq) dropwise. After stirring the reaction mixture for 5h

at -78oC, allylboronic acid pinacol ester (0.77mL, 4.09mmol, 1.2eq) (2) was added dropwise. The reaction mixture

was further stirred at -78oC for 1h and then allowed to warm to room temperature. A solution of MgBr2.OEt2 in Et2O,

made as follows, was added to the reaction mixture at this point: [1,2-dibromoethane (0.60mL, 6.88mmol, 1.0eq) was

added to a suspension of magnesium (0.17g, 6.88mmol, 1.0eq) in Et2O (8.6mL) at room temperature. The reaction

flask was then placed into a water bath in order to control the moderate exotherm and was further stirred for 2h]. Both

layers of the biphasic mixture thus obtained were transferred to the former mixture via syringe. The mixture was

refluxed for 16h.

The reaction mixture was allowed to cool down to room temperature and was carefully quenched with water. Et2O

was added, the layers were separated and the aqueous phase was extracted with Et2O. The combined organic layers

were washed with 1N HCl, 1N NaOH, water and brine, dried (MgSO4), concentrated and purified by column

chromatography (SiO2) to obtain the pure 2-(1-(4-methoxyphenyl)hex-5-en-3-yl)-4,4,5,5-tetramethyl-1,3,2-

dioxaborolane (3) (0.81g, 75.3%) as colorless oil. The reaction is given in Figure 1.

Complete characterization was done by taking 1H NMR,

13C NMR and IR. It was used as starting material for reaction

(Figure 2, 3).

IR (film): ν (cm–1

) 3026 (sp2C-H Stretch), 2977, 2924, 2852 (sp

3 C-H Stretch), 1511, 1456(sp

2 C=C Stretch), 1243,

1175, 1142 (sp3C-O Stretch), 846, 822, 670 (sp

2 C-H oop bending).

1H NMR (400 MHz, CDCl3) δ ppm 7.09 (2H, d, J=8.80 Hz, 2 ArH) 6.81 (2H, d, J=8.80 Hz, 2 ArH) 5.86 – 5.75

(1H, m, CH=CH2) 5.04 (1H, d, J=2.20 Hz, CH=CHH) 4.94 (1H, d, J=10.27 Hz, CH=CHH) 3.78 (3H, s, OCH3) 2.63 -

2.48 (2H, m, ArCH2CH2CHBCH2) 2.27 - 2.11 (2H, m, ArCH2CH2CHBCH2) 1.78 - 1.58 (2H, m, ArCH2CH2CHBCH2)

1.25 (12H, s, 4 CH3) 1.08 - 1.18 (1H, m, ArCH2CH2CHBCH2) 13

C NMR (100 MHz, CDCl3) δ ppm 157.6 (1C, -OCH3), 138.4 (2C, 2 ArCH), 135.0 (2C, 2 ArCH), 129.2 (1C,

ArC-O), 114.9 (1C, -CH2CH=CH2), 113.6 (1C, -CH=CH2), 83.0 (2C, 2 C(CH3)2), 55.2 (1C, ArCCH2), 35.3 (1C, -

CH2CH2CHB), 34.5 (1C, -CH2CHB), 33.1 (1C, -CHBCH2CH), 24.9 (1C, -CH2CH2CHB), 24.8 (4C, 2 (CH3)2C). 11

B NMR (96.23 MHz, None) δ ppm 33.24

16

15

14

13

18

17

12

11

10

19

20

21

B5

O1

23

O4

6

78

9

O22

23 H21a

H21b

H14.Proton.esp

7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0

Chemical Shift (ppm)

0

0.05

0.10

0.15

Norm

alized Inte

nsity

1.0711.982.092.342.113.131.001.010.992.052.01

M05(s,23)

M02(m,17,15)

M01(m,18,14)

M11(d,21b)

M09(s,9,8,6,7)

M04(d,21a)

M10(m,10)

M03(m,20) M06(m,12)

M07(m,19)

M08(m,11)

1.1

21.1

21.1

41.1

51.1

61.2

51.6

41.6

51.6

61.6

81.6

91.7

11.7

31.7

42.1

62.1

82.2

12.5

42.5

52.5

62.5

72.5

92.6

0

3.7

8

4.9

34.9

34.9

54.9

65.0

05.0

05.0

45.0

4

5.0

5

5.7

55.7

75.8

05.8

1

5.8

45.8

6

6.7

96.8

06.8

26.8

3

7.0

87.0

87.1

17.1

1

1H-NMR

Frequency (MHz): 399.77

Solvent: Chloroform-d

2-(1-(4-methoxyphenyl)hex-5-en-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (3)

118

Hussain et al, 2015

16

15

14

13

18

17

O22

23

12

11

10

19

20

21

B5

O1

23

O4

6

78

9

h14.Carbon.esp

152 144 136 128 120 112 104 96 88 80 72 64 56 48 40 32 24 16 8 0


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Norm

alized Inte

nsity

157.6

0(2

3)

138.4

4(1

5,1

7)

135.0

2(1

4,1

8)

129.2

4(1

6)

114.9

1(2

0)

113.6

5(2

1)

83.0

3(3

,2)

77.3

377.0

276.7

0 55.2

3(1

3)

35.3

8(1

2)

34.5

0(1

0)

33.1

7(1

9)

24.8

8(1

1)


13C-NMR



16

15

14

13

18

17

O22

23

12

11

10

19

20

21

B5

O1

23

O4

6

78

9

h14.Boron-NMR.esp

95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Norm

alized Inte

nsity

33.2

4

11B NMR


Solvent: None


2.3. Synthesis and Characterization of (E)-tert-butyl 7-(4-methoxyphenyl)-5-(4,4,5,5-tetramethyl-1,3,2-

dioxaborolan-2-yl)hept-2-enoate (5) To a solution of allyl boronic ester (0.75g, 2.37mmol, 1.0eq) (3) and tert. butyl acrylate (0.75mL, 4.74mmol, 2.0eq)

(4) in CH2Cl2 (30mL) was added Grubbs-Hoveyda II (0.027g, 0.043mmol, 0.02eq) (4a). The flask was fitted with a

condenser and refluxed under nitrogen for 15h. Reaction was monitored by TLC. The reaction mixture was then

reduced in volume to 0.5mL and purified directly on a silica gel column eluting with 9:1 Pet. Ether/ EtOAc to get the

desired product (E)-tert-butyl 7-(4-methoxyphenyl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hept-2-enoate

(0.78g, 78.82%) (5)14

.

The product (5) was completely characterized by

1H NMR,

13C NMR and IR.

119



) 2977, 2930 (sp3 C-H Stretch), 1711 (sp

2C=O Stretch), 1651, 1612 (C-C=C Stretch), 1512,

1456(sp2 C=C Stretch), 1244, 1214, 1139 (sp

3C-O Stretch), 849, 822, 682 (sp

2 C-H oop bending).

1H NMR (400 MHz, CDCl3) δ ppm 7.08 (2H, d, J=8.56 Hz, 2 ArH) 6.85 (1H, t, J=7.21 Hz, CH=CHCOO ) 6.81

(2H, d, J=8.56 Hz, 2 ArH) 5.73 (1H, dt, J=15.41, 1.47 Hz, , CH=CHCOO) 3.77 (3H, s, OCH3) 2.62-2.47 (2H, m,

ArCH2CH2CHBCH2), 2.36-2.21 (2H, m, ArCH2CH2CHBCH2) 1.78-1.57 (2H, m, ArCH2CH2CHBCH) 1.46 (9H, s, 3

CCH3) 1.24 (12H, s, 4 CCH3) 1.21-1.16 (1H, m, ArCH2CH2CHBCH2) 13

C NMR (100 MHz, CDCl3) δ ppm 165.9 (1C, COO) 157.6 (1C, ArC) 147.5 (1C, CH=CHCOO) 134.6 (1C, ArC)

129.2 (2C, 2 ArCH) 123.5 (1C, CH=CHCOO) 113.6 (2C, 2 ArCH) 83.2 (2C, 2 C(CH3)2) 79.8 (1C, C(CH3)3)

55.2 (1C, OCH3) 34.3 (1C, ArCH2CH2CHBCH2) 33.5 (1C, ArCH2CH2CHBCH2) 33.1 (3C, C(CH3)3) 28.1 (4C, 2

C(CH3)2) 24.82 (1C, ArCH2CH2CHBCH2) 24.81 (1C, ArCH2CH2CHBCH2). 11


HRMS (ESI) calcd. for C24H37BO5 [M+H]+ 417.2811, found 417.2811.

16

15

14

13

18

17

12

11

10

19

20

21

B5

O1

23

O4

6

78

9

O26

27

22

O23

O28

24

25

29

30

H15.Proton.esp

7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0


0

0.05

0.10

0.15

Norm

alized Inte

nsity

1.0911.418.342.622.252.262.881.052.400.672.00

M09(s)M05(s)

M10(s)

M01(d)

M02(t)

M03(d)

M04(dt)

M11(m)

M06(m)

M07(m)

M08(m)

1.1

71.1

91.2

11.2

4

1.4

6

1.6

31.6

51.7

21.7

32.2

52.2

72.2

92.5

12.5

32.5

42.5

62.5

72.5

82.6

0

3.7

7

5.7

15.7

15.7

55.7

5

6.8

06.8

26.8

56.8

7

7.0

77.0

9

(E)-tert-butyl 7-(4-methoxyphenyl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hept-2-enoate (5)

1H-NMR



16

15

14

13

18

17

12

11

10

19

20

21

B5

O1

23

O4

6

78

9

O26

27

22

O23

O28

24

25

29

30

H15.Carbon.esp

168 160 152 144 136 128 120 112 104 96 88 80 72 64 56 48 40 32 24 16 8 0


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Norm

alized Inte

nsity

24.8

124.8

2

28.1

4

33.1

733.5

634.3

4

55.2

3

76.6

877.0

077.3

279.8

083.2

6

113.6

9

123.5

7

129.2

4

134.6

3

147.5

7

157.6

6

165.9

7


13C-NMR



120

Hussain et al, 2015

16

15

14

13

18

17

12

11

10

19

20

21

B5

O1

23

O4

6

78

9

O26

27

22

O23

O28

24

25

29

30

H15.Boron-NMR.esp

95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0


-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Norm

alized Inte

nsity

29.5

4


11B-NMR


Solvent: None


2.4 Synthesis and Characterization of (E)-diethyl (6-(4-methoxyphenyl)-4-(4,4,5,5-tetramethyl-1,3,2-

dioxaborolan-2-yl)hex-1-en-1-yl)phosphonate (7) To a solution of allyl boronic ester (0.10g, 0.316mmol, 1.0eq) (3) and diethyl vinylphosphonate (0.12mL, 0.632mmol,

2.0eq) (6) in CH2Cl2 (20mL) was added Grubbs-Hoveyda II (0.0039g, 0.0063mmol, 0.02eq) (4a). After fitting a

condenser to the flask, reaction mixture was refluxed under nitrogen for 15h. Reaction completion was monitored by

TLC. The reaction mixture was then reduced in volume to 0.5mL and purified directly on a silica gel column eluting

with 9:1 Pet. Ether/ EtOAc to get pure (E)-diethyl (6-(4-methoxyphenyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-

yl)hex-1-en-1-yl)phosphonate (0.11g, 79%) (7)13

.

121


1H NMR,

13C NMR and IR were taken to characterize (E)-diethyl (6-(4-methoxyphenyl)-4-(4,4,5,5-tetramethyl-1,3,2-

dioxaborolan-2-yl)hex-1-en-1-yl)phosphonate (7).


) 2978, 2930 (sp3 C-H Stretch), 1630, 1612 (C-C=C Stretch), 1512, 1443 (sp

2 C=C Stretch), 1242,

1166, 1142 (sp3C-O Stretch), 960, 821, 731 (sp

2 C-H oop bending).

1H NMR (400 MHz, CDCl3) δ ppm 7.10 (2H, d, J=8.61 Hz, 2 ArH) 6.83 (2H, d, J=8.61 Hz, 2 ArH) 6.80-6.70

(1H, m, CH=CHPO) 5.73-5.61 (1H, m, CH=CHPO) 4.12-4.02 (4H, m, 2 CH2CH3) 3.80 (3H, s, OCH3) 2.66-2.50

(2H, m, ArCH2CH2CHBCH2) 2.46-2.27 (2H, m, ArCH2CH2CHBCH2) 1.80-1.59 (2H, m, ArCH2CH2CHBCH) 1.32

(6H, td, J=7.15, 1.65 Hz, 2 CH2CH3) 1.27 (12H, s, 4 CCH3) 1.25-1.20 (1H, m, ArCH2CH2CHBCH2). 13

C NMR (100 MHz, CDCl3) δ ppm 157.6 (1C, ArC-O), 153.3 (CH=CHPO), 134.5 (1C, ArC), 129.2 (2C, 2

ArCH), 118.1 (1C, CH=CHPO), 116.2 (2C, 2 ArCH), 113.7 (2C, 2 C(CH3)2), 83.3 (2C, 2 CH2CH3), 61.5, 61.4

(1P, d, CHPO), 55.2 (1C, OCH3), 35.6 (1C, ArCH2CH2CHBCH2), 34.2 (1C, ArCH2CH2CHBCH2), 33.0 (1C,

ArCH2CH2CHBCH2), 24.8 (4C, 2 C(CH3)2), 16.38 (1C, ArCH2CH2CHBCH2), 16.31 (2C, 2 CH2CH3). 11


HRMS (ESI) calcd. for C23H38BO6P [M+H]+ 453.2574, found 453.2574.

16

15

14

13

18

17

O26

27

12

11

10

19

20

21

B5

O1

23

O4

8

9 6

7

P22

O31

O23

O28

29

30

24

25

H26.Proton.esp

7.5 7.0 6.5 6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0


0

0.05

0.10

0.15

Norm

alized Inte

nsity

1.2911.406.162.412.122.082.804.021.030.872.001.81

M06(s) M11(s)

M02(d)

M01(d)

M10(td)

M12(m)

M05(m)

M03(m)

M04(m) M07(m)

M08(m)

M09(m)

1.2

11.2

31.2

41.2

71.3

21.3

31.3

41.6

51.6

81.7

41.7

51.7

62.3

32.3

92.4

12.5

42.5

52.5

62.5

72.5

82.5

92.6

12.6

5

3.8

04.0

24.0

34.0

54.0

74.0

94.1

04.1

1

5.6

25.6

25.6

75.6

8

5.7

25.7

2

6.8

26.8

4

7.0

97.1

1

(E)-diethyl (6-(4-methoxyphenyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hex-1-en-1-yl)phosphonate (7)

1H-NMR



2.5 Equipments To take

1H NMR and

13C NMR measurements Varian NMR (400 MHz) spectrometer was used. Chemical shifts for

protons were measured .Relative to tetramethylsilane (TMS) at δ= 0 ppm all chemical shift for protons were

measured.

3. RESULTS AND DISCUSSION First allylic boronic ester (3) was synthesized by Lithiation-borylation methodology mentioned in section 4.2 by

reacting Carbamate (1) with allylboronic ester (2) as colorless oil in excellent yields (75.3%) (table 1, entry 1).

Conditions for this reaction are given in figure 1.

Table-1: Data of Starting Materials

Entry Starting Material Color Yield (%)

1 2-(1-(4-methoxyphenyl)hex-5-en-3-yl)-4,4,5,5-tetramethyl-1,3,2-

dioxaborolane Colorless oil 75.3

122

Hussain et al, 2015

16

15

14

13

18

17

12

11

10

19

20

21

B5

O1

23

O4

6

78

9

O26

27

P22

O31

O23

O2829

30

2425

H26.Carbon.esp

168 160 152 144 136 128 120 112 104 96 88 80 72 64 56 48 40 32 24 16 8 0


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Norm

alized Inte

nsity

16.3

216.3

8

24.8

6

33.0

734.2

635.6

6

55.2

4

61.4

461.5

0

76.6

877.0

077.3

2

83.3

1

113.7

0116.2

9118.1

5

129.2

2

134.5

6

153.3

1

157.6

8


13C-NMR



16

15

14

13

18

17

12

11

10

19

20

21

B5

O1

23

O4

6

78

9

O26

27

P22

O31

OEt23

OEt24

H26.Boron-NMR.esp

95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0Chemical Shift (ppm)

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Norm

alized Inte

nsity

29.7

3


11B-NMR


Solvent: None

Allylic boronic ester (3) was used as starting material for the synthesis of novel compounds. (E)-tert-butyl 7-

(4-methoxyphenyl)-5-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hept-2-enoate (5) and (E)-diethyl (6-(4-

methoxyphenyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hex-1-en-1-yl)phosphonate (7) were

synthesized by reacting boronic ester (3) with tert-butyl acrylate (4) and diethyl vinylphosphonate (6).

Chemical reactions with detailed conditions are mentioned in figure 2 and 3 respectively.

Table-2: Yields of Products

Entry Boronic Ester Reagents Products Yield (%)

1

78.82

2

79

123


16

15

14

13

18

17

12

11

10

19

20

21

B5

O1

23

O4

6

78

9

O26

27

P22

O31

O23

O2829

30

2425


For the product (E)-diethyl (6-(4-methoxyphenyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)hex-1-en-1-

yl)phosphonate (7), yield was quite high (table 2, entry 2) while for (E)-tert-butyl 7-(4-methoxyphenyl)-5-(4,4,5,5-

tetramethyl-1,3,2-dioxaborolan-2-yl)hept-2-enoate (5) yield was comparable (table 2, entry 1) and reasonably high.

Both novel compounds (5, 7) were characterized by 1H NMR,

13C NMR,

11B NMR and IR; detailed study of which is

given in section 4.3 and 4.4.

4. CONCLUSIONS In the recent study, two novel compounds (E)-tert-butyl 7-(4-methoxyphenyl)-5-(4,4,5,5-tetramethyl-1,3,2-

dioxaborolan-2-yl)hept-2-enoate (5) and (E)-diethyl (6-(4-methoxyphenyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-

2-yl)hex-1-en-1-yl)phosphonate (7) were synthesized in excellent yields by olefin cross metathesis. These compounds

could have applications as starting materials for asymmetric synthesis. Presence of electron withdrawing groups in

these compounds could promote cyclopropanation and cyclopentanation. For the product (5) yield was 78.82% (table

2, entry 1) while for the other product (7) yield was slightly great 79% (table 2, entry 2).

5. ACKNOWLEDGMENT Financial support provided by the Higher Education Commission of Pakistan is warmly acknowledged. Authors

moreover acknowledge the Department of Chemistry, University of Engineering and Technology, Lahore-Pakistan;

Superior University Raiwand Road Lahore-Pakistan and University of Bristol, Bristol, U.K for guidance, research and

laboratory facilities.

6. REFERENCES 1. Chauvin, Y., Angew Chem, Int Ed. (2006), 45, 3740-3747, http://dx.doi.org/10.1002/anie.200601234.

2. Schrock, R. R., Angew Chem, Int Ed. (2006), 45, 3748-3759, http://dx.doi.org/10.1002/anie.200600085.

3. Grubbs, R. H., Angew Chem, Int Ed. (2006), 45, 3760-3765, http://dx.doi.org/10.1002/anie.200600680.

4. Hoveyda, A. H., Zhugralin, A. R. Nature (2007), 450, 243-251, http://dx.doi.org/10.1038/nature06351.

5. Furstner, A., Angew. Chem., Int. Ed. (2000), 39, 3012-3043, http://dx.doi.org/10.1002/1521-

3773(20000901)39:17<3012::AID-ANIE3012>3.0.CO;2-G.

6. Grubbs, R. H., Tetrahedron (2004), 60, 7117-7140, http://dx.doi.org/10.1016/j.tet.2004.05.124.

7. Trnka, T. M., Grubbs, R. H. Acc. Chem. Res. (2001), 34, 18-29, http://dx.doi.org/10.1021/ar000114f.

8. Herrison, J. L., Chauvin, Y. Makromol. Chem. (1971), 141, 161-167,

http://dx.doi.org/10.1002/macp.1971.021410112.

9. Connon, S. J., Blechert, S. Angew. Chem. Int. Ed. (2003), 42, 1900-1923,

http://dx.doi.org/10.1002/anie.200200556.

10. Schrodi, Y., Pederson RL Aldrichimica Acta. (2007), 40, 45-52.

124

http://dx.doi.org/10.1002/anie.200601234



http://dx.doi.org/10.1038/nature06351

http://dx.doi.org/10.1002/1521-3773%2820000901%2939:17%3C3012::AID-ANIE3012%3E3.0.CO;2-G

http://dx.doi.org/10.1002/1521-3773%2820000901%2939:17%3C3012::AID-ANIE3012%3E3.0.CO;2-G

http://dx.doi.org/10.1016/j.tet.2004.05.124

http://dx.doi.org/10.1021/ar000114f

http://dx.doi.org/10.1002/macp.1971.021410112


Hussain et al, 2015

11. Scholl, M., Ding, S., Lee, C. W., Grubbs, R. H., Org Lett. (1999), 6, 953,

http://dx.doi.org/10.1021/ol990909q. 12. Voigtritter, K., Ghorai, S., Lipshutz, B. H., J Org Chem. (2011), 76(11), 4697-4702,

http://dx.doi.org/10.1021/jo200360s.

13. Abbasi, M. A., Aziz-ur-Rehman, Muhmood, T., Khan, K. M., Ashraf, M., Ejaz, S. A., Arshad, S., J. Chem.

Soc. Pak. (2013), 35(2), 404.

14. Lipshutz, B. H., Ghorai, S., Boskovic, Z. V., Tetrahedron (2008), 64, 6949-6954,

http://dx.doi.org/10.1016/j.tet.2008.04.027.

125

http://dx.doi.org/10.1021/ol990909q

http://dx.doi.org/10.1021/jo200360s

http://dx.doi.org/10.1016/j.tet.2008.04.027

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