Conjugated imines and iminium salts as versatile acceptors of nucleophiles
作者:Makoto Shimizu、Iwao Hachiya、Isao Mizota
DOI:10.1039/b814930e
日期:——
development of synthetic methodologies where nucleophilicaddition reactions to imino carbons are utilized in crucial steps. This article summarizes double nucleophilicaddition reactions with alpha,beta-unsaturated aldimines, addition reactions using alkynyl imines, "umpoled" reactions of alpha-imino esters, and the use of iminium salts as reactive electrophiles.
Asymmetric Petasis Borono‐Mannich Allylation Reactions Catalyzed by Chiral Biphenols
作者:Yao Jiang、Scott E. Schaus
DOI:10.1002/anie.201611332
日期:2017.2
Chiral biphenols catalyze the asymmetric Petasis borono‐Mannich allylation of aldehydes and amines through the use of a bench‐stable allyldioxaborolane. The reaction proceeds via a two‐step, one‐pot process and requires 2–8 mole % of 3,3′‐Ph2‐BINOL as the optimal catalyst. Under microwave heating the reaction affords chiral homoallylic amines in excellent yields (up to 99 %) and high enantioselectivies
Prolinate Salt as a Catalyst in the<i>syn</i>-Selective, Asymmetric Mannich Reaction of Alkynyl Imine
作者:Yujiro Hayashi、Tatsuya Yamazaki、Genki Kawauchi、Itaru Sato
DOI:10.1021/acs.orglett.8b00728
日期:2018.4.20
Prolinate salt is an efficient catalyst in the Mannichreaction of alkynyl imine and aldehyde, to afford synthetically useful chiral propargyl amine derivatives with excellent syn-selectivity and nearly perfect control of the absolute configuration. The counterion of the prolinate salt does not affect the enantioselectivity. This is a rare example, in which proline alkali metals, alkaline-earth metals
The synthesis of multi-substituted 2-iminopyridines by conjugate addition of ethyl cyanoacetatederivatives to alkynyl imines has been developed. The reaction of ethyl cyanoacetatederivatives with alkynyl imines provided multi-substituted 2-iminopyridines in good yields. Also described is the transformation of 2-iminopyridines into 2-aminopyridines by deprotection of the substituent on the nitrogen
Enolate dianion of diethyl (S)-malate was stereoselectively condensed with nonenoiizable N-arylimines to give 2-pyrrolidinonederivatives. The presence of HMPA changes the diastereoselectivity of this cyclization reaction.