Asymmetric Retro-Claisen Reaction by Synergistic Chiral Primary Amine/Palladium Catalysis
作者:Yanfang Han、Long Zhang、Sanzhong Luo
DOI:10.1021/acs.orglett.9b02491
日期:2019.9.20
We described herein a chiral primaryamine/palladium catalyzed asymmetric retro-Claisen reaction of β-diketones with salicylic carbonates. A series of chiral α-alkylated ketones and macrolides were obtained with good yields and excellent enantioselectivities upon a sequence of decarboxylative benzylation, retro-Claisen cleavage, and enamine protonation. This strategy features broad substrate scope
iron(III) triflate, Fe(OTf)3, copper(II) triflate, Cu(OTf)2, and silver(I) triflate, AgOTf, show high catalytic activities. These reactions proceed through the carbon–carbonbondcleavage by a retro‐aldol reaction and were found to be highly regioselective even in the presence of other functional groups. This type of reaction can also be applied to the preparation of the keto esters during the synthesis