A new route to ± quadrone

Abstract

A new route t o +_ quadrone (1) is reported which relies on an intramolecular radical cyclisation t o provide the required axial carboxylic acid in the Danishefsky intermediate (2).

Synthesis of Polyquinane Natural Products: An Update

“…A vinyl radical cyclization (86 f 87) was the key reaction in Parsons and Neary's 48 novel approach to Scheme 13 34 Scheme 14 38 Scheme 15 39 Scheme 16 40…”

“…In 1989, Magnus and co-workers 60 reported an approach to (()-pentalenolactone-H (104) (Scheme Scheme 20 48 Scheme 21 49 Scheme 22 50 Recently, Paquette and co-workers 62,63 have reported the first total synthesis of the (()-pentalenolactone-P methyl ester (130), a novel sesquiterpene 52h containing a cyclopropane ring fused to the diquinane moiety (Scheme 30). The desired skeleton was assembled starting from the 1-methylnorcaradiene-dimethyl fumarate [4+2]-cycloadduct 131 which was obtained through a stereo-and regioselective high pressure Diels-Alder reaction.…”

Quadrane Sesquiterpenes: Natural Sources, Biology, and Syntheses

“…[38] The readily available β-keto ester 70 was successively alkylated in both enolizable positions and decarboxylated, and the resulting silyl ether was converted into an aldehyde to give 83. A base-promoted intramolecular aldolization provided the desired bicyclo[3.2.1]octanol as a diastereomeric mixture, which was dehydrated to give 84.…”