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Highly Selective Nucleophilic 4‐Aryl ‐2,3‐allenylation of Malonates †
Author(s) -
Song Shihua,
Ma Shengming
Publication year - 2020
Publication title -
chinese journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 1001-604X
DOI - 10.1002/cjoc.202000300
Subject(s) - chemistry , enantioselective synthesis , chemoselectivity , aryl , nucleophile , cycloisomerization , combinatorial chemistry , selectivity , ligand (biochemistry) , catalysis , organic chemistry , biochemistry , alkyl , receptor
Summary of main observation and conclusion Allenes are a class of very important compounds and the development of straightforward, efficient, and highly enantioselective synthetic strategies for allenes have attracted extensive interests. Along this line, it is well known that aryl‐substituted allenes may be readily racemized, thus, difficult to prepare in high ee. Herein, an efficient palladium‐catalyzed nucleophilic allenylation of malonates with racemic 4‐aryl‐2,3‐butadienyl carbonates has been developed. The selectivity issue of mono‐ vs . bis‐allenylation with 2‐non‐substituted malonates has been addressed. By utilizing ( R )‐(–)‐DTBM‐SEGPHOS (5,5'‐bis[di(3,5‐di‐ t ‐butyl‐4‐methoxyphenyl)phosphino]‐4,4'‐bi‐1,3‐benzodioxole) as a chiral ligand, various aryl‐substituted allenes and bisallenes have been prepared with good to excellent yields with high chemoselectivity and enantioselectivity under mild reaction conditions. Au‐catalyzed cycloisomerization and APK (allenic Pauson–Khand) reactions affording optically active mono‐ and bicyclic products have been demonstrated.