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Asymmetric Synthesis of the 1‐ epi Aglycon of the Cripowellins A and B
Author(s) -
Enders Dieter,
Lenzen Achim,
Raabe Gerhard
Publication year - 2005
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.200500556
Subject(s) - stereochemistry , dihydroxylation , intramolecular force , metathesis , ring closing metathesis , bicyclic molecule , chemistry , total synthesis , yield (engineering) , heck reaction , enantioselective synthesis , palladium , organic chemistry , catalysis , polymer , materials science , metallurgy , polymerization
The unusual [5.3.2]bicyclic structure of the insecticidal Amaryllidaceae alkaloids cripowellins A and B has been synthesized for the first time by a sequence of Sharpless dihydroxylation, ring‐closing metathesis (RCM), and intramolecular Heck reaction (see scheme). The asymmetric synthesis of the 1‐ epi aglycon proceeds with virtually complete diastereo‐ and enantioselectivity (≥98 % de , ≥98 % ee ) in 13 steps and an overall yield of 5.6 %.