Organocatalytic Nucleophilic Substitution Reaction of <i>gem</i>-Difluoroalkenes with Ketene Silyl Acetals
作者:Azusa Kondoh、Kazumi Koda、Masahiro Terada
DOI:10.1021/acs.orglett.9b00566
日期:2019.4.5
An organocatalytic nucleophilic substitution reaction of gem-difluoroalkenes with ketene silyl acetals was developed. Phosphazene P4-tBu effectively catalyzed the reaction under mild conditions to provide monofluoroalkenes possessing an alkoxycarbonylmethyl group in high yields with high Z selectivities.
开发了宝石-二氟烯烃与乙烯酮甲硅烷基缩醛的有机催化亲核取代反应。磷腈P4- t Bu在温和条件下有效催化了该反应,以高收率和高Z选择性提供了具有烷氧羰基甲基的一氟烯烃。
Regio- and Stereoselective Carboindation of Internal Alkynyl Ethers with Organosilicon or -stannane Nucleophiles
and reduces the activation energy. Many types of carbon nucleophiles such as silyl ketene acetals, silyl ketene imines, a silyl cyanide, an alkynyl stannane, and an allylic stannane were applicable to the present reaction system to give highly functionalized metalated enol ethers (β-alkoxyalkenylindiums). The prepared β-alkoxyalkenylindiums were transformed to various functionalized tetrasubstituted
Herein, a coupling reaction of enol ethers with silyl ketene imines in the presence of catalytic amounts of InBr3 and Me3SiBr is described. Kinetic studies have revealed that an indium catalyst and Me3SiBr accelerated the coupling process and the regeneration of the catalyst, respectively. Various types of enol ethers and silyl ketene imines are applicable. In addition, a formal synthesis of verapamil
Enantioselective Construction of Quaternary Stereogenic Carbons by the Lewis Base Catalyzed Additions of Silyl Ketene Imines to Aldehydes
作者:Scott E. Denmark、Tyler W. Wilson、Matthew T. Burk、John R. Heemstra
DOI:10.1021/ja077134y
日期:2007.12.1
Silyl ketene imines derivedfrom a variety of alpha-branched nitriles have been developed as highly useful reagents for the construction of quaternary stereogenic centers via the aldol addition reaction. In the presence of SiCl4 and the catalytic action of chiral phosphoramide (R,R)-5, silyl ketene imines undergo extremely rapid and high yielding addition to a wide variety of aromatic aldehydes with
A highly enantioselective Mannich reaction of silyl ketene imines with isatin‐derived ketimines has been realized by using a chiral N,N′‐dioxide/ZnII catalyst. A variety of β‐amino nitriles containing congested vicinal tetrasubstituted stereocenters were obtained with excellent outcomes (up to 98 % yield, >19:1 d.r. and 99 % ee). Based on the experimental investigations, a possible transition state