KHSO<sub>4</sub>-Mediated Condensation Reactions of <i>tert</i>-Butanesulfinamide with Aldehydes. Preparation of <i>tert</i>-Butanesulfinyl Aldimines
作者:Yong Qin、Zhiyan Huang、Min Zhang、Yin Wang
DOI:10.1055/s-2005-865234
日期:——
tert-butanesulfinyl aldimines 1 were prepared by direct condensation of chiral tert-butanesulfinamide 3 with aldehydes 2 in high yields in the presence of KHSO 4 . The main advantage of KHSO 4 is that it is applicable to the condensation reactions of a variety of aldehydes, including electron deficient and electron rich (hetereo)aromatic aldehydes, as well as aliphatic aldehydes.
Diastereoselective Pomeranz–Fritsch–Bobbitt synthesis of (S)-(−)-O-methylbharatamine using (S)-N-tert-butanesulfinimine as a substrate
作者:Agnieszka Grajewska、Maria D. Rozwadowska
DOI:10.1016/j.tetasy.2007.11.010
日期:2007.12
The protoberberine-type alkaloid, (S)-(-)-O-methylbharatamine, has been synthesized in six steps involving the addition of laterally lithiated o-toluamide to (S)-N-tert-butanesulfinimine as the crucial process. The target alkaloid was obtained in 24.4% overall yield with 88% ee. (c) 2007 Elsevier Ltd. All rights reserved.
Highly Diastereoselective Enolate Addition of O-Protected α-Hydroxyacetate to (<i>S</i><i><sub>R</sub></i>)-<i>tert-</i>Butanesulfinylimines: Synthesis of Taxol Side Chain
[GRAPHICS]The taxol side chain (S-R,2R,3S)-N-tert-butanesulfinyl-O-Boe-3-phenylisoserine benzyl ester 4c was synthesized through a lithium enolate addition of O-Boc-alpha-hydroxyacetate benzyl ester 5c to benzylidene (S-R)-tert-butanesulfinamide 6a in excellent yield and diastereoselectivity. By similar approach, a series of enantiopure 3-substituted isoserine benzyl esters 4 useful for the semi-syntheses of taxol derivatives were also prepared in high to excellent yields and diastereoselectivities. The diastereoselective addition mechanism was discussed on the basis of the experimental observation.
Synthesis of enantiomerically pure aryl, hetero aryl and alkyl sulfinimides catalyzed by recyclable tungstophosphoric acid
A simple and efficient procedure was developed for the preparation of a variety of aryl, hetero aryl and alkyl N-sulfinylimines (2b-2u) with excellent yields (85–94%) using tungstophosphoric acid as catalyst. Also, this new synthetic protocol features high conversion, shorter reaction time, a straight forward and simple work up procedure. Catalyst was recycled for 10 times without much loss in activity