Catalysis of Mukaiyama Aldol Reactions by a Tricyclic Aluminum Alkoxide Lewis Acid
作者:Steven M. Raders、John G. Verkade
DOI:10.1021/jo9009134
日期:2009.8.7
The Mukayiama aldolreaction of aldehydes is efficiently accomplished with a low concentration of the dimeric alumatrane catalyst 2 at mild or subambient temperatures. Our protocol tolerates a wide variety of electron-rich, neutral, and deficient aryl, alkyl, and heterocyclic aldehydes. A wide variety of enol silyl ethers are also tolerated. An intermediate that was isolated provides mechanistic information
[2 + 2] Cycloaddition of <i>o</i>-Carboryne with Vinyl Ethers: Synthesis of Carborane-Fused Cyclobutanes
作者:Jie Zhang、Zuowei Xie
DOI:10.1021/acs.organomet.0c00163
日期:2020.12.14
precursor, o-carboryne undergoes an efficient [2 + 2] cycloaddition with a large variety of vinylethers at room temperature to give a series of carborane-fused cyclobutanes in very good to high isolated yields. This reaction is compatible with many functional groups and has a very broad substrate scope ranging from alkyl- to aryl- and to silyl-substituted vinylethers. A stepwise reaction mechanism is proposed
Photoredox Catalysis: A Mild, Operationally Simple Approach to the Synthesis of α-Trifluoromethyl Carbonyl Compounds
作者:Phong V. Pham、David A. Nagib、David W. C. MacMillan
DOI:10.1002/anie.201101861
日期:2011.6.27
A facile and efficient method for the α‐trifluoromethylation of carbonylcompounds and enolsilanes has been accomplished through application of a photoredox catalysis strategy. A one‐flask procedure for the direct α‐trifluoromethylation and α‐perfluoroalkylation of ketone, amide, and ester substrates as well as silylketene acetals is described (see scheme).
Addition of sulfinylated and sulfonylated carbon centered radicals to alkenes and enolethers
作者:Philippe Renaud
DOI:10.1016/s0040-4039(00)97686-x
日期:1990.1
(p-Tolylsulfonyl)- and (p-tolylsulfinyl)methylradicals reacted with electron rich olefins like vinylsilane, enolethers and silylenolethers in the presence of Bu3SnH to give addition products. Cyclization of sulfonylated and sulfinylated radicals proceeded in good yield and high trans stereoselectivity in the case of enolethers.
The direct arylation of allylic sp3 C–H bonds via organic and photoredox catalysis
作者:James D. Cuthbertson、David W. C. MacMillan
DOI:10.1038/nature14255
日期:2015.3.5
particular, the direct arylation of non-functionalized allylic systems would enable access to a series of known pharmacophores (molecular features responsible for a drug’s action), though a general solution to this long-standing challenge remains elusive. Here we report the use of both photoredox and organic catalysis to accomplish a mild, broadly effective direct allylic C–H arylation. This C–C bond forming
未活化的 sp3 C-H 键的直接功能化仍然是合成有机化学家面临的最具挑战性的问题之一。这种转变的吸引力来自于它们通过简单和其他惰性结构单元的耦合促进复杂有机分子构建的能力,而不会引入无关的官能团。尽管最近做出了显着的努力,但事实证明,为 sp3 C-H 键参与 C-C 键形成反应建立一般和温和的策略是困难的。在此背景下,发现能够以催化方式直接使烯丙基甲基、亚甲基和次甲基碳官能化的化学转化是当务之急。尽管烯丙基 C-H 键的直接氧化和胺化方案(即,C-H 键,其中相邻的碳参与 C = C 键)已经广泛建立,烯丙基底物在 C-C 键形成反应中的参与迄今为止需要使用预官能化的偶联伙伴。特别是,非功能化烯丙基系统的直接芳基化将能够获得一系列已知的药效团(负责药物作用的分子特征),尽管解决这一长期挑战的通用解决方案仍然难以捉摸。在这里,我们报告了使用光氧化还原和有机催化来完成温和、广泛有效的直接烯丙基