Cysteine-Derived Organocatalyst in a Highly Enantioselective Intramolecular Michael Reaction
摘要:
Asymmetric intramolecular Michael reaction catalyzed by an organocatalyst derived from cysteine has been developed for the synthesis of chiral bicyclo[4.3.0]nonene and cis-disubstituted cyclopentane skeletons with a creation of three or two contiguous chiral centers in good yield with high diastereo- and excellent enantioselectivities.
Cysteine-Derived Organocatalyst in a Highly Enantioselective Intramolecular Michael Reaction
摘要:
Asymmetric intramolecular Michael reaction catalyzed by an organocatalyst derived from cysteine has been developed for the synthesis of chiral bicyclo[4.3.0]nonene and cis-disubstituted cyclopentane skeletons with a creation of three or two contiguous chiral centers in good yield with high diastereo- and excellent enantioselectivities.
Simple proline-derived anilide-catalyzed asymmetric -intramolecular Michael reaction was described. Chiral cyclic keto-aldehydes were obtained from acyclic formyl enones in excellent yields with good stereoselectivity. The reaction proceeded in exceptionally fast with a commercially available proline anilide. On the other hand, the longer reaction time conduced toward the higher -diastereoselectivity
Catalytic Asymmetric Reductive Michael Cyclization
作者:Jung Woon Yang、Maria T. Hechavarria Fonseca、Benjamin List
DOI:10.1021/ja055735o
日期:2005.11.1
reduction-Michael cyclization of enal enones has been developed. Accordingly, treating the enal enone with a Hantzsch dihydropyridine in the presence of a catalytic amount of an imidazolidinone organocatalyst provides cyclic keto aldehydes in high yields and enantiomeric excesses. The reaction works well with aliphatic and aromatic substrates in the synthesis of five- and six-membered carbacyclic derivatives.