Catalytic Enantioselective Vinylogous Allylic Alkylation of Coumarins
作者:Satavisha Kayal、Santanu Mukherjee
DOI:10.1021/acs.orglett.7b02421
日期:2017.9.15
An unprecedented, organocatalytic enantioselective vinylogous γ-allylic alkylation of 4-methylcoumarins has been developed. Using allylic carbonates as the allyl source, this reaction is catalyzed by Lewis basic dimeric Cinchona alkaloid (QD)2PHAL and proceeds exclusively in a γ- and branched-selective manner to produce densely functionalized coumarin derivatives generally in good yields with good
Iridium-catalyzed enantioselective direct vinylogous allylic alkylation of coumarins
作者:Rahul Sarkar、Sankash Mitra、Santanu Mukherjee
DOI:10.1039/c8sc02041h
日期:——
first iridium-catalyzed enantioselective vinylogous allylicalkylation of coumarins is presented. Using easily accessible linear allylic carbonates as the allylic electrophile, this reaction installs unfunctionalized allyl groups at the γ-position of 4-methylcoumarins in an exclusively branched-selective manner generally in high yields with an excellent level of enantioselectivity (up to 99 : 1 er).