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Total Synthesis of Pteridic Acids A and B
Author(s) -
Nakahata Takashi,
Fujimura Shohei,
Kuwahara Shigefumi
Publication year - 2006
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200600134
Subject(s) - streptomyces hygroscopicus , epimer , enantioselective synthesis , yield (engineering) , total synthesis , stereochemistry , chemistry , aldol reaction , derivative (finance) , acetic acid , natural product , streptomyces , organic chemistry , biology , catalysis , bacteria , genetics , materials science , economics , financial economics , metallurgy
Pteridic acid A ( 1 ) is a spirocyclic octaketide produced by the phytoepiphytic actinomycete Streptomyces hygroscopicus TP‐A0451 and possesses potent plant‐growth‐promoting activity comparable to that of indole‐3‐acetic acid. The enantioselective total synthesis of this natural product was achieved by employing the Sn(OTf) 2 ‐mediated Evans aldol reaction and the Fukuyama acetylenic coupling reaction as the key CC bond‐forming steps producing 1 through a 14‐step sequence in 22 % overall yield from a known oxazolidinone derivative. MgBr 2 ‐mediated equilibration of an anomerically favored spirocyclic intermediate used for the synthesis of 1 brought about partial epimerization of the spirocenter to give the corresponding anomerically disfavored epimer, which was converted into pteridic acid B (11‐ epi ‐ 1 ), another plant‐growth promoter of the same microbial origin.