Steric control of alpha- and beta-alkylation of azulenone intermediates in a guanacastepene a synthesis.
The origins of different stereoselectivities observed experimentally in the alkylations of azulenone precursors in the guanacastepene A synthesis have been determined through density functional theory investigations. The optimized transition structures of methylation of two different guanacastepene A precursors show that steric effects, rather than torsional factors that often determine such stereoselectivities, dictate the preferred products observed.
Wang
Hao
H
Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA.
Michalak
Karol
K
Michalak
Michał
M
Jiménez-Osés
Gonzalo
G
Wicha
J
J
Houk
K N
KN
D000478:Alkylation; D052176:Azulenes / Q000737:chemistry*; D004224:Diterpenes / Q000138:chemical synthesis / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
D052176:Azulenes; D004224:Diterpenes; C409194:guanacastepene