Chiral β-Keto Propargylamine Synthesis via Enantioselective Mannich Reaction of Enamides with <i>C</i>-Alkynyl <i>N</i>-Boc <i>N</i>,<i>O</i>-Acetals
作者:Fang-Fang Feng、Shen Li、Chi Wai Cheung、Jun-An Ma
DOI:10.1021/acs.orglett.9b03181
日期:2019.10.18
Propargylamines are an important class of compounds in organic synthesis and drug discovery, yet the synthesis of chiral β-keto propargylamines remains underdeveloped. Herein, we describe a streamlined and general enantioselective Mannichreaction of enamides with C-alkynyl N-Boc N,O-acetals, which serve as readily available C-alkynyl imine precursors, to access a broad range of chiral β-keto N-Boc-propargylamines
addition-cyclization-elimination cascade is developed, that allows various 2,6-diaryl-4-perfluoroalkylpyridines to be synthesized in one step from easily available enamides and perfluorocarboxylic anhydrides. The procedure is also operationally simple and scalable and provides access to the facial construction of 4-fluoroalkylpyridines, which are of great interest in medicinal chemistry.
Catalytic Asymmetric Access to Noncanonical Chiral α-Amino Acids from Cyclic Iminoglyoxylates and Enamides
作者:Yue Zhang、Jun-Kuan Li、Fa-Guang Zhang、Jun-An Ma
DOI:10.1021/acs.joc.0c00436
日期:2020.4.17
Mannich reaction of cyclic iminoglyoxylates with enamides by virtue of chiral phosphoric acid catalysis in a one-pot manner. The wide substrate scope, mild reaction conditions, and constantly excellent enantioselectivities (>95% ee in most cases) render this protocol highly practical for the rapid construction of valuable noncanonical chiral α-amino-acid building blocks.
Enantioselective Addition of Enamides to Cyclic Ketimines: Access to Chiral 3,3‐Disubstituted Isoindolin‐1‐Ones
作者:Fang‐Fang Feng、Jin‐Shan Li、Shen Li、Jun‐An Ma
DOI:10.1002/adsc.201900710
日期:2019.9.17
An enantioselectiveaddition of enamides to cyclicketimines generated in situ from 3‐hydroxyisoindolin‐1‐ones was developed. This reaction takes advantage of readily available substrates, mild reaction conditions, as well as enlarged reaction generality, affording chiral 3,3‐disubstituted isoindolin‐1‐ones with a quaternary stereogenic center in high yields (up to 98%) and enantioselectivities (up