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.
A New Synthetic Method for α-Alkoxycarbonyl Iminium Salt and Its Reaction with Nucleophiles
作者:Makoto Shimizu、Hiroyuki Itou、Megumi Miura
DOI:10.1021/ja042330f
日期:2005.3.1
An iminium salt was easily prepared using the oxidation of amino ketene silyl acetal with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone, and the subsequent nucleophilic addition to this iminium species proceeded efficiently to afford alpha-amino esters in good yields.
Double Nucleophilic Addition of Azide and Tetraallyltin to the Latent α,β-Unsaturated Aldehydes Using in situ Hydrolysis of the Imino Functionality Promoted by Tin(IV) Chloride Pentahydrate
作者:Makoto Shimizu、Takafumi Nishi
DOI:10.1055/s-2004-820023
日期:——
In the presence of SnCl4·5H2O and acetic acid, a mixture of trimethylsilyl azide and tetraallyltin underwent 1,4- and subsequently 1,2-addition, respectively, with the α,β-unsaturated aldimines to give 1,3-hydroxy azides in good yields, where the hydrolysis of the intermediary imino species was found to be crucial.
Double Nucleophilic Addition of Azide and Tetramethallyltin to α,β-Unsaturated Aldimines Promoted by Aluminum Chloride
作者:Makoto Shimizu、Chiaki Yamauchi、Toshiki Ogawa
DOI:10.1246/cl.2004.606
日期:2004.5
In the presence of AlCl 3 , a mixture of hydrogen azide and tetramethallyltin underwent 1,4- and subsequently 1,2-addition, respectively, with α,β-unsaturated aldimines to give 1,3-amino azides in good yields. The 1,3-amino azides thus obtained were readily converted into 1,3-diamines by reduction with LiAlH 4 .
Chromium [II]-mediated reductive cleavage of a tertiary halide bearing three β-alkoxy groups. Synthesis of the north hexacyclic steroid unit of the cephalostatin family
作者:Seongkon Kim、Scott C. Sutton、P.L. Fuchs
DOI:10.1016/0040-4039(95)00307-x
日期:1995.4
17nat, a hexacyclic steroid bearing the requisite functionality and spiroketal stereochemistry of the North portion of the cephalostatin family is described. The key reaction involves CrCl2 mediated reductive cleavage of a tertiary bromide which is beta to three alkoxy groups.