Biosynthesis of the indolizidine alkaloid, cyclizidine
Abstract
The 1H and 13C n.m.r. spectra of cyclizidine (1) have been completely assigned and incorporation experiments with 13C-labelled sodium acetate and propionate and sodium [3-2H3]propionate have revealed that the entire carbon skeleton of (1) is derived from these precusors by a polyketide-type biosynthetic pathway, with the cyclopropyl ring being derived from a single propionate unit.