- Asymmetric Rh(II)-catalyzed cyclopropanation of alkenes with diacceptor diazo compounds: P -methoxyphenyl ketone as a general stereoselectivity controlling group
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Different diacceptor diazo compounds bearing an α-PMP-ketone group were found to be effective carbene precursors for the highly stereoselective Rh2(S-TCPTTL)4-catalyzed cyclopropanation of alkenes (EWG = NO2, CN, CO2Me). The resulting products were readily transformed into a variety of biologically relevant enantiopure molecules, such as cyclopropane α- and β-amino acid derivatives. Different mechanistic studies carried out led to a rationale for the high diastereo- and enantioselectivity obtained, where the PMP-ketone moiety was found to play a critical role in the stereoinduction process. Additionally, the use of catalytic amounts of achiral Lewis bases to influence the enantioinduction of the reactions developed is documented.
- Lindsay, Vincent N. G.,Nicolas, Cyril,Charette, Andre B.
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supporting information; experimental part
p. 8972 - 8981
(2011/08/04)
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- Experimental evidence for the all-up reactive conformation of chiral rhodium(II) carboxylate catalysts: Enantioselective synthesis of cis-cyclopropane α-amino acids
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(Chemical Equation Presented) Useful empirical insights onto the enantioinduction process of chiral Rh(II)-carboxylate catalysts are described in the first catalytic asymmetric cyclopropanation of alkenes with α-nitro diazoacetophenones. X-ray, solution N
- Lindsay, Vincent N. G.,Lin, Wei,Charette, Andre B.
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supporting information; experimental part
p. 16383 - 16385
(2010/02/16)
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- Asymmetric cyclopropanations by rhodium(II) N-(arylsulfonyl)prolinate catalyzed decomposition of vinyldiazomethanes in the presence of alkenes. Practical enantioselective synthesis of the four stereoisomers of 2-phenylcyclopropan-1-amino acid
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The rhodium N-(arylsulfonyl)prolinate catalyzed decomposition of vinyldiazomethanes in the presence of alkenes leads to a very general method for the synthesis of functionalized cyclopropanes in a highly diastereoselective and enantioselective mode. A det
- Davies, Huw M. L.,Bruzinski, Paul R.,Lake, Debra H.,Kong, Norman,Fall, Michael J.
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p. 6897 - 6907
(2007/10/03)
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