Premium
Phosphine‐Catalyzed [4+1] Cycloadditions of Allenes with Methyl Ketimines, Enamines, and a Primary Amine
Author(s) -
Cao ZeHun,
Wang YuHao,
Kalita Subarna Jyoti,
Schneider Uwe,
Huang YiYong
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201912263
Subject(s) - chemistry , regioselectivity , electrophile , phosphine , catalysis , phosphonium , enamine , geminal , amine gas treating , primary (astronomy) , double bond , medicinal chemistry , organic chemistry , catalytic cycle , organocatalysis , combinatorial chemistry , enantioselective synthesis , physics , astronomy
Unprecedented phosphine‐catalyzed [4+1] cycloadditions of allenyl imides have been discovered using various N‐based substrates including methyl ketimines, enamines, and a primary amine. These transformations provide a one‐pot access to cyclopentenoyl enamines and imines, or (chiral) γ‐lactams through two geminal C−C bond or two C−N bond formations, respectively. Several P‐based key intermediates including a 1,4‐(bis)electrophilic α,β‐unsaturated ketenyl phosphonium species have been detected by 31 P NMR and HRMS analyses, which shed light on the postulated catalytic cycle. The synthetic utility of this new chemistry has been demonstrated through a gram‐scaling up of the catalytic reaction as well as regioselective hydrogenation and double condensation to form cyclopentanoyl enamines and fused pyrazole building blocks, respectively.