Toward a Synthesis of Fawcettimine-Type Lycopodium Alkaloids: Stereocontrolled Synthesis of a Functionalized Azaspirocycle Precursor

Abstract

The stereocontrolled synthesis of a new azaspirocycle precursor of the fawcettimine-type Lycopodium alkaloids is described. Our approach provides an efficient entry to the azaspirocycle via a cascade Wacker-allylation sequence followed by a highly stereoselective Claisen rearrangement. This azaspirocycle, bearing all of the requisite functionality with pivotal stereogenic centers, is considered to be a versatile precursor useful for the fawcettimine-type Lycopodium alkaloids.

Recently Isolated Fawcettimine-Type Alkaloids

“…They synthesised azaspirocycle via cascade Wacker-allylation sequence followed by a highly stereo-selective Claisen rearrangement (Figure 8). 20 Synthesis of Lycopoclavamine-A, Fawcettimine-type alkaloid with a β-methyl group at C-15 and a trans-decahydroquinoline ring system at the A/D-ring junction, has been attempted by Zaimoku and Taniguchi in 2014, where they proceeded via Diels−Alder reaction. 21 Recently, Kaneko et al 2019 attempted successful asymmetric synthesis of Lycopoclavamine-A via stereoselective Pauson−Khand Reaction (PKR) and conjugate addition to construct a quaternary C-12.…”