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Asymmetric Synthesis of Sappanin‐Type Homoisoflavonoids
Author(s) -
Lee Jungeun,
Kwon Sangil,
Seo SeungYong
Publication year - 2020
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.202000097
Subject(s) - chemistry , desymmetrization , enantioselective synthesis , kinetic resolution , transfer hydrogenation , aldol reaction , asymmetric hydrogenation , asymmetric carbon , stereochemistry , enol , catalysis , ruthenium , cycloisomerization , racemization , organic chemistry , optically active
Homoisoflavanones, 3‐benzylchroman‐4‐ones, which are naturally occurring sappanin‐type homoisoflavonoids, possess a 16‐carbon skeleton and a single chiral center. In this paper, we present various asymmetric synthesis of homoisoflavanones that have been developed. The first approach is a lipase‐catalyzed desymmetrization of 2‐benzylpropane‐1,3‐diol and its diacetate. Three approaches for the synthesis of an optically active 3‐benzylchroman‐4‐one are asymmetric protonation of the silyl enol ether derived from a racemic homoisoflavanone, iridium‐catalyzed asymmetric hydrogenation of α‐phenoxymethylcinnamic acid, and Evans asymmetric aldol reaction. Recently, our group performed Noyori ruthenium‐catalyzed asymmetric transfer hydrogenation with dynamic kinetic resolution, followed by alcohol oxidation of 3‐benzylchroman‐4‐ol.