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Catalytic C-C Bond Formation via Capture of Hydrogenation Intermediates Answer Key to Problems. Michael J. Krische Presented by Louis-Philippe Beaulieu Université de Montréal April 14 th 2009. Answer Key to Problem 1. Cho, C. W.; Krische, M. J. Org. Lett. 2006 , 8 , 3873-3876. - PowerPoint PPT Presentation
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Michael J. Krische
Presented byLouis-Philippe BeaulieuUniversité de Montréal
April 14th 2009
Catalytic C-C Bond Formation via Capture of Hydrogenation Intermediates
Answer Key to Problems
Answer Key to Problem 1
2 Cho, C. W.; Krische, M. J. Org. Lett. 2006, 8, 3873-3876.
Ph TMS H
OOEt
O Rh(COD)2OTf (5 mol%)(R)-Cl,MeO-BIPHEP (5 mol%)
H2 (1 atm)DCE, 25 C
0.40 0.33 0.75 0.89LUMO
HOMO 0.68 0.66 0.07 0.03
Ph TMS
H
O
OEtOH
+TMS Ph
H
O
OEtOH
74% yield 93% ee99: 1 rr
Ph TMS
Ph TMSRhILn
Ph
TMS
RhIIILn
O
O
OEt
Ph TMS
LnRhIII
O
OEtO
H2Ph TMS
LnRhIII
O
OEtOH
H
RhILn
Ph TMS
H
O
OEtOH
Answer Key to Problem 2
3 Jang, H. Y.; Krische, M. J. J. Am. Chem. Soc. 2004, 126, 7875-7880.Jang, H. Y.; Hughes, F. W.; Gong, H.; Zhang, J.; Brodbelt, J. S.; Krische, M. J. J. Am. Chem. Soc. 2005, 127, 6174-6175.
RhIIILn
Ph
LnRhI
Carbonyl insertion mechanism
H2
PhRhILn
Ph
PhHRhIII(H)Ln
RhIIILn
Ph
Ph
Ph
MeO2CMeO2C
MeO2CMeO2CPh
Ph
MeO2CMeO2C
MeO2CMeO2C
Ph
Ph
MeO2CMeO2C
H
Ph
HMeO2CMeO2C
BC23H22O4
PhTsN
Rh(COD)2OTfrac-BINAP
D2DCE, 25 C
1
TsN
Ph
D
RhIIILnDTsN
A B
RhIIILn
Ph
Me
Me
TsNMe
Cycloisomerization product
No deuterium incorporation
Ph
H
Et
5 mol% catalyst loading: 52% yield (42% alkyne reduction)100 mol% catalyst loading: 45% yield (8% alkyne reduction)
Answer Key to Problem 3
4 Jang, H. Y.; Huddleston, R. R.; Krische, M. J. Angew. Chem., Int. Ed. 2003, 42, 4074-4077.
LnRhIX
D2 -DX
LnRhID DH
RhILn
O
O
R
DH
OLnRhI
DH
OLn(H)RhIIICOR COR
DH
HO
LnRhI
COR
D2DH
HO
Ln(D)2RhIII
COR
LnRhI(D)
LnRhI(D) DH
HOCOR
DH
HOCOR
DH
D H
OO
(1 equiv)
[Rh(COD)2OTf] (5 mol%)(p-OMePh)3P (10 mol%)
D2 (1 atm)DCE, 25 C(5 equiv)
O
OH
O
OH
(1:1)
DD
D
D
Answer Key to Problem 4
5 Hong, Y. T.; Barchuk, A.; Krische, M. J. Angew. Chem., Int. Ed. 2006, 45, 6885-6888.
Ph
O
Ph O
O
Ph
O
Ph
OPh
Me
LnRhI
Ph
LnRhIII
Ph O
PhOCO
Ph
LnRhIII
PhOCO
H2
PhCO2H, BasePh
O Ph
LnRhIII
H
Oxidative Addition Mechanism
Ph O
O
Ph
O PhRh(COD)2BARF (2 mol%)Ph3As (4.4 mol%)
iPr2NEt (2 equiv)H2 (1 atm)(MeOCH2CH2)O, 65C C
C15H14O
PhPh
O
Me
PhLn(D)RhI
LnRhI Ph
H
Ph O
O
Ph
O
Ph
H
LnRhIII
PhOCO
OPhPh
OPh
Me
LnRhIXH2
LnRhIIIX(H)2
LnRhIH
Ph
Hydrometallative Mechanism
Base, -HX
Answer Key to Problem 5
6 Skucas, E.; Kong, J. R.; Krische, M. J. J. Am. Chem. Soc. 2007, 129, 7242-7243.
(Ts)(Boc)NOH
1
(Ts)(Boc)N TsNH NTs+ HC
CH
TsN
2
TsNH NTs+ HC
CHTsN
