Cooperative organocatalysis of Mukaiyama-type aldol reactions by thioureas and nitro compounds
作者:Konstantin V. Bukhryakov、Victor G. Desyatkin、Valentin O. Rodionov
DOI:10.1039/c6cc01984f
日期:——
A unique organocatalytic system for Mukaiyama-type aldol reactions based on the cooperative action of nitrocompounds and thioureas has been identified. This system is compatible with a wide range of...
Reversal of Chemoselectivity in Organotin Lewis Acid-Catalyzed Reaction of Ketene Silyl Acetal with Aldehyde and α-Enal
作者:Jianxie Chen、Junzo Otera
DOI:10.1055/s-1997-715
日期:——
The organotin Lewis acid-catalyzed reaction of ketene silyl acetal with aldehydes results in reversal of chemoselectivity: α-enals react preferentially or exclusively in competition with an alkanal or even aromatic aldehydes.
[1,2-Benzenediolato(2−)-<i>O</i>-<i>O</i>′]oxotitanium. A Chemoselective and Efficient Catalyst for Aldol-type Reaction of Ketene Silyl Acetals with Aldehydes
作者:Ryuichiro Hara、Teruaki Mukaiyama
DOI:10.1246/cl.1989.1909
日期:1989.11
In the presence of a catalytic amount of [1,2-benzenediolato(2−)-O,O′]oxotitanium, ketene silyl acetals smoothly react with aldehydes to afford the corresponding β-hydroxy carboxylic esters in good yields under mild conditions. According to this procedure, an aldehyde group is selectively activated, while an acid labile acetal group remains intact.
Organotin perchlorates as gentle Lewis acid catalysts in Mukaiyama reaction
作者:Jian-xie Chen、Junzo Otera
DOI:10.1016/s0040-4020(97)00995-2
日期:1997.10
aldehydes, an electron-donating group increases the reactivity of aldehyde while the reverse is true with an electron-withdrawing group. These are opposite to the reactivity order in nucleophilic addition to free carbonyls. In contrast to ketene silyl acetal, enol silyl ethers derived from ketones are not activated by organotin perchlorates. Thus, these two enol silyl ethers can be discriminated from each
Photocatalytic Vicinal Aminopyridylation of Methyl Ketones by a Double Umpolung Strategy
作者:Honggu Im、Wonjun Choi、Sungwoo Hong
DOI:10.1002/anie.202008435
日期:2020.9.28
umpolung strategy for the vicinal aminopyridylation of ketones was developed using pyridinium N−N ylides. The inversion of the polarity of the pyridinium N−N ylides by single‐electron oxidation successfully enables radical‐mediated 1,3‐dipolar cycloadditions with enolsilanes formed in situ from ketones, followed by homolytic cleavage of the N−N bond. Intriguingly, the nucleophilic amino and electrophilic