Novel fragmentation reaction of correolide.
[reaction: see text] Pentacyclic triterpenoid natural product correolide (1) was converted to ketone 2 via ozonolysis. An unusual fragmentation reaction of ketone 2 with LiCl was discovered. This reaction is general among several similar substrates examined and appears to be specific for the correolide-type E-ring structure (ketone). A mechanism involving a retroaldol reaction, a nucleophilic opening of the epoxide, and a subsequent acetoxy elimination reaction was proposed.
Bao
Jianming
J
Department of Medicinal Chemistry, Merck Research Laboratories, P.O. Box 2000, Rahway, New Jersey 07065, USA. bao_jianming@merck.com
Baker
Robert K
RK
Doss
George A
GA
Kayser
Frank
F
Kotliar
Andrew
A
Miao
Shouwu
S
Parsons
William H
WH
Rupprecht
Kathleen M
KM