Z-Selective α-Arylation of α,β-Unsaturated Nitriles via [3,3]-Sigmatropic Rearrangement
Z-Selective α-Arylation of α,β-Unsaturated Nitriles via [3,3]-Sigmatropic Rearrangement
复制标题
通过 3,3-Sigmatropic 重排对 α,β-不饱和腈进行 Z 选择性 α-芳基化
DOI：
10.1002/anie.202010740
复制
发表时间：
2020-11-24
影响因子：
16.6
通讯作者：
Peng, Bo
中科院分区：
文献类型：
--
作者：
Chen, Mengyuan;Liang, Yuchen;Peng, Bo
Morita-Baylis-Hillman（MBH）反应和[3，3]-σ迁移重排反应是有机合成中的两个典型反应。我们合并了这两类反应，实现了芳基亚砜与α，β-不饱和腈的[3，3]-重排。该反应通过依次用亲电活化剂（Tf 2 O）和碱处理两种偶联配偶体来实现，提供了一种有效的方法来合成具有Z-选择性的多功能α-芳基α，β-不饱和腈，其通过直接α-C-H芳基化未改性的α，β-不饱和腈。控制实验和密度泛函理论计算支持四阶段反应序列，包括Tf 2 O活化的芳基亚砜与α，β-不饱和腈的组装、类MBH刘易斯碱加成、[3，3]-重排和E1 cB-消除.其中，刘易斯碱加成反应是非对映选择性的，E1 cB消除反应是顺式选择性的，这可能是反应具有显著Z-选择性的原因。
The Morita-Baylis-Hillman (MBH) reaction and [3, 3]-sigmatropic rearrangement are two paradigms in organic synthesis. We have merged the two types of reactions to achieve [3,3]-rearrangement of aryl sulfoxides with alpha,beta-unsaturated nitriles. The reaction was achieved by sequentially treating both coupling partners with electrophilic activator (Tf2O) and base, offering an effective approach to prepare synthetically versatile alpha-aryl alpha,beta-unsaturated nitriles with Z-selectivity through direct alpha-C-H arylation of unmodified alpha,beta-unsaturated nitriles. The control experiments and DFT calculations support a four-stage reaction sequence, including the assembly of Tf2O activated aryl sulfoxide with alpha,beta-unsaturated nitrile, MBH-like Lewis base addition, [3,3]-rearrangement, and E1cB-elimination. Among these stages, the Lewis base addition is diastereoselective and E1cB-elimination is cis-selective, which could account for the remarkable Z-selectivity of the reaction.