title: A strategy for complex dimer formation when biomimicry fails: total synthesis of ten coccinellid alkaloids.
abstract: Although dimeric natural products can often be synthesized in the laboratory by directly merging advanced monomers, these approaches sometimes fail, leading instead to non-natural architectures via incorrect unions. Such a situation arose during our studies of the coccinellid alkaloids, when attempts to directly dimerize Nature's presumed monomeric precursors in a putative biomimetic sequence afforded only a non-natural analogue through improper regiocontrol. Herein, we outline a unique strategy for dimer formation that obviates these difficulties, one which rapidly constructs the coccinellid dimers psylloborine A and isopsylloborine A through a terminating sequence of two reaction cascades that generate five bonds, five rings, and four stereocenters. In addition, a common synthetic intermediate is identified which allows for the rapid, asymmetric formal or complete total syntheses of eight monomeric members of the class.
authors: Department of Chemistry, Columbia University , 3000 Broadway, New York, New York 10027, United States.
authors: Trevor C
authors: TC
authors: Sherwood
authors: Adam H
authors: AH
authors: Trotta
authors: Scott A
authors: SA
authors: Snyder
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D040761:Biomimetic Materials / Q000737:chemistry*; D019281:Dimerization; D008968:Molecular Conformation
chemical_list: D000470:Alkaloids