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The First Total Synthesis of Sophoflavescenol, Flavenochromane C, and Citrusinol
Author(s) -
Nguyen VanSon,
Dong LinPei,
Wang ShengChun,
Wang Qiuan
Publication year - 2015
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201403689
Subject(s) - prenylation , chemistry , claisen rearrangement , regioselectivity , stereochemistry , dehydrogenation , benzoquinone , total synthesis , aldol reaction , medicinal chemistry , combinatorial chemistry , organic chemistry , catalysis , enzyme
The first total syntheses of sophoflavescenol ( 1 ), flavenochromane C ( 2 ), and citrusinol ( 3 ) were achieved. These three naturally occurring prenylated or prenyl‐cyclized flavonoids have important biological activities such as cytotoxicity against some cancer cell lines, or are lead compounds for the treatment of erectile dysfunction. Starting from 2,4,6‐trihydroxyacetophenone and substituted benzaldehydes, the synthesis involved methoxymethyl protection, aldol condensation, cyclization, oxidation with dimethyldioxirane, O ‐prenylation, microwave‐assisted Claisen rearrangement, deprotection, cyclization of the prenyl group, and dehydrogenation with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone. The overall yields of 1 , 2 , and 3 were 23, 17, and 16 %, respectively. All compounds were characterized by 1 H and 13 C NMR spectroscopy and MS. The key step of the synthetic route was a regioselective microwave‐assisted Claisen rearrangement to form an 8‐prenylated flavonoid from a 5‐ O ‐prenylflavonoid.