Organocatalyzed regioselective and enantioselective synthesis of 1,4- and 1,2-dihydropyridines
作者:Truong-Giang Le、Hoai-Thu Pham、James P. Martin、Isabelle Chataigner、Jean-Luc Renaud
DOI:10.1080/00397911.2020.1778034
日期:2020.9.1
first examples of asymmetric organocatalyzed synthesis of 1,2-dihydropyridines, affording enantioselective access to and partially solving regioselectivity challenges in the synthesis of dihydropyridines. We demonstrate that through modification of organocatalysts both 1,2- and 1,4-dihydropyridines (1,2- and 1,4-DHPs) can be obtained with high regioselectivity (ratio of 1,2-DHP/1,4-DHP from 95/5 to 0/100)
Dual enantioselective Diels–Alder process in the cyclization of chiral acrylamide with dienes
作者:Doo Young Jung、Doo Han Park、Sung Han Kim、Yong Hae Kim
DOI:10.1002/poc.828
日期:2004.11
Diels–Alder cycloadditions of chiralacrylamides with cyclopentadiene or 2, 3-dimethyl butadiene proceed with high diastereofacial selectivity. Either endo-R or endo-S products have been obtained depending upon the structures of acrylamides and Lewis acids used. The endo form was exclusively obtained over the exo form. The dependence of the mechanism of formation of opposite configurations of endo-R
Process for the preparation of 1,3,2-oxazaborolidine compounds
申请人:Burgos Alain
公开号:US20080139851A1
公开(公告)日:2008-06-12
A process is used for the preparation of 1,3,2-oxazaborolidine compounds.
This process prepares compounds of formula (I) or (IA):
in which:
R1 is an alkyl or an aryl; and
R2, R3, R4 and R5 are especially a hydrogen atom or an alkyl,
wherein the following are reacted in two steps:
a) a boric precursor compound with an acetal compound to give a boronate compound; and
b) the boronate compound with an amino alcohol compound.
This process avoids by-products and exhibits a very good stereospecificity.
Highly Efficient Asymmetric Michael Reaction of Aldehydes to Nitroalkenes with Diphenylperhydroindolinol Silyl Ethers as Organocatalysts
作者:Ren-Shi Luo、Jiang Weng、Hui-Bing Ai、Gui Lu、Albert S. C. Chan
DOI:10.1002/adsc.200900355
日期:2009.10
perhydroindole derivatives were synthesized in good yields and evaluated as chiral catalysts in the asymmetricMichaelreaction of aldehydes to nitroalkenes. (2S,3aS,7aS)-Diphenylperhydroindolinol silylether 10 facilitated the reaction of a wide range of aldehyde and nitroalkene substrates, providing Michael adducts in nearly optically pure form (99% ee), good yields and high diastereoselectivities (syn/anti
Enantioselective catalytic borane reductions of achiral ketones: Syntheses and application of two chiral β-amino alcohols from (S)-2-indoline carboxylic acid
The synthesis of (S)-alpha,alpha-diphenyl-(indolin-2-yl)methanol 1 makes available the chiral oxazaborolidine 2 which is an excellent catalyst for borane reduction of prochiral ketones to chiral secondary alcohols, e.g. acetophenone, in high optical purity The new chiral auxiliary 1 is sythesized from (S)-2-indoline carboxylic acid in a two step procedure. (S)-(Indolin-2-yl)methanol 3 is converted to the oxazaborolidine 4 which served also as an enantioselective catalyst in the reduction of aromatic ketones with BH3.THF.