Direct Access to Highly Enantioenriched α-Branched Acrylonitriles through a One-Pot Sequential Asymmetric Michael Addition/Retro-Dieckmann/Retro-Michael Fragmentation Cascade
摘要:
A highly enantioselective synthesis of alpha-branched acrylonitriles is reported featuring a one-pot sequential asymmetric Michael addition/retro-Dieckmann/retro-Michael fragmentation cascade. The method, which relies on a solid, bench-stable, and commercially available acrylonitrile surrogate, is practical, scalable, and highly versatile and provides a direct access to a wide range of enantioenriched nitrite-containing building blocks. Most importantly, the method offers a new tool to incorporate an acrylonitrile moiety in an asymmetric fashion.
Asymmetric Umpolung (3+2) Cycloadditions of Iminoesters with α,β-Unsaturated-2-acyl Imidazoles for the Synthesis of Substituted Pyrrolidines
作者:Mamta Gill、Arko Das、Vinod K. Singh
DOI:10.1021/acs.orglett.2c01438
日期:2022.8.12
enantioselective (3+2) cycloaddition reaction of iminoesters occurring with opposite regioselectivity is reported. This reaction provides chiral polysubstituted pyrrolidines with high enantioselectivities (up to 97%), diastereoselectivities (>20:1), and yields (up to 99%). Interestingly, changing the alpha-substituents of the iminoesters from an aryl to an aliphatic (benzyl) group or hydrogen resulted
Enantioselective synthesis of substituted 1-pyrrolines via Michael addition of iminoesters with α,β-unsaturated 2-acyl imidazoles catalyzed by chiral Cu(I)-BPE complex
作者:Mamta Gill、Vinod K. Singh
DOI:10.1016/j.tetlet.2023.154555
日期:2023.6
A highly chemo-, diastereo-, and enantioselective Cu(I)-1,2-Bis((2S,5S)-2,5-diphenylphospholano)ethane (BPE) catalyzed Michael addition of iminoesters to α, β-unsaturated 2-acyl imidazoles at 0 °C and subsequent silica-assisted cyclization of Michael adducts into highly functionalized 1-pyrrolines bearing two contiguous stereocenters (up to >20: 1 cr, > 20: 1 dr, and 99% ee) has been described.
一种高度化学、非对映和对映选择性的 Cu(I)-1,2-双((2 S ,5 S )-2,5-二苯基膦基)乙烷 (BPE) 催化亚氨基酯迈克尔加成到α , β -不饱和0 °C 下的2-酰基咪唑和随后的二氧化硅辅助迈克尔加合物环化成带有两个连续立体中心的高度功能化的 1-吡咯啉(高达 >20: 1 cr,> 20: 1 dr,和 99% ee)已被描述.
A General Strategy for the Synthesis of Truxinate Natural Products Enabled by Enantioselective [2+2] Photocycloadditions
作者:Matthew J. Genzink、Matthew D. Rossler、Herman Recendiz、Tehshik P. Yoon
DOI:10.1021/jacs.3c07132
日期:2023.9.6
Pseudodimeric cyclobutanes constitute a large class of natural products that could, in principle, be efficiently synthesized via [2+2] photocycloadditions. However, the difficulty in developing chemo-, regio-, diastereo-, and enantioselective cycloadditions has limited their use in asymmetric syntheses. Herein, we show that chiral acid catalysts promote highly selective visible-light photocycloadditions