ABSTRACT
The [7-5-5] tricyclic core of the Daphniphyllum alkaloids was constructed, featuring a Claisen-Ireland rearrangement to install the two contiguous stereogenic centers, E1cB elimination to form the tetrasubstituted C-C double bond, and a 2,3-Wittig rearrangement to construct the quaternary carbon. Ring-closing metathesis and an intramolecular carbonyl ene reaction were employed for construction of the requisite ring system.
Subject(s)
Alkaloids/chemistry , Alkaloids/chemical synthesis , Daphniphyllum/chemistry , Chemistry Techniques, Synthetic , Cyclization , StereoisomerismABSTRACT
The first total synthesis of (-)-lepistine has been accomplished in 11 steps from (S)-glycidol. The synthesis features construction of the 10-membered ring via an intramolecular epoxide opening by nosylamide, regioselective dehydration to form an enol ether, and construction of the aminal moiety induced by cleavage of the nosyl groups.
