Asymmetric synthesis of unsaturated monocyclic and bicyclic nitrogen heterocycles

Hydrolysis of scalemic trichloroacetamides Cl₃CCONHCH(R)CHCH₂ and allylation, or acylation with but-3-enoic acid, followed by ring-closing metathesis resulted in the formation of unsaturated pyrrolidine and piperidine building blocks. These were employed in the synthesis of (S)-coniine (R = Pr) and a formal synthesis of (+)-anisomycin (R = p-MeOC₆H₄). Extension of this methodology with R = CH₂CHCH₂ employing two ring-closing metatheses resulted in the synthesis of unsaturated quinolizidinone and indolizidinone frameworks.