Short racemic syntheses of calvine and epicalvine

The intramolecular Pd(II)-catalysed carbonylation of aminoalkenitol was used as a key step in the short racemic syntheses of the ladybird beetle alkaloids calvine and epicalvine. The title compounds have been prepared in 26% overall yield over four steps starting from hexanal and pentenyl bromide.

The ladybird beetle alkaloids calvine and epicalvine were prepared in racemic form in 26% combined overall yield over four steps starting from hexanal and pentenyl bromide.