Yuichi Shiratori

Steroselective synthesis of the basic skeleton of aphidicolan diterpenes: synthetic approach to aphidicolin

Abstract The basic skeleton of aphidicolan-type diterpenes was stereoselectively synthesized via thermolysis of a benzocyclobutene.

An intramolecular diels-alder approach to quassinoids—a stereoselective construction of a-aromatic klaineanone

Abstract Thermolysis of a benzocyclobutene derivative ( 20 ) prepared from norcamphor produced stereoselectively a tetracyclic compound ( 2 ), which was converted to a lactone ( 21 ) having correct stereochemistry at C7, C8, C9, C11, C13, and C14 positions of (±)-klaineanone.

Stereoselective synthesis of the basic skeleton of aphidicolan-type diterpenes via intramolecular Diels–Alder cyclisation. Synthetic approach to aphidicoline

The basic tetracyclic skeleton of aphidicolan-type diterpenes has been synthesised by an intramolecular Diels–Alder reaction of 1-(1-cyano-5-methoxy-3-methylbenzocyclobuten-1-yl)hept-6-en-3-one (9). The cyclised product (10) was converted into the tetracyclic compound (11) by treatment with base followed by acid hydrolysis. The stereochemistry of (11) was easily determined from the n.m.r. spectral data, in which one of the aromatic protons was observed to be deshielded by the five-membered ketone moiety. Thus benzocyclobutene thermolysis again proved to be a powerful method for the construction of a complex molecule.