An Intramolecular Para-Phenolic Allylation Free Radical Cyclization Strategy for the Synthesis of Alkaloids and Terpenes With Spiro[4.5] Decane Architectures

Matthew G. Donahue, University of Southern Mississippi
Nicholas G. Jentsch, University of Southern Mississippi
Erin C. Realini, University of Southern Mississippi

Abstract

A Tsuji-Trost variant of the Winstein-Masamune reaction has been investigated for the synthesis of the AC spirocyclic ring system 9bearing a quaternary carbon found in the fawcettimine type Lycopodiumalkaloids magellanine 1 and lycojaponicumin B 2 and cyclopiane diterpenes such as conidiogenone 3. Annulation of the B ring for the synthesis of tricyclic ABC cores was demonstrated utilizing a 5-exo-trig free radical cyclization of a primary carbon radical onto a cyclohexadienone generated with tri-n-butylgermanium hydride (9 → 11).

Graphical abstract