Asymmetric Synthesis of Unsaturated Monocyclic and Bicyclic Nitrogen Heterocycles
摘要:
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-MeOC5H4). Extension of this methodology with R = CH2CHCH2 employing two ring-closing metatheses resulted in the synthesis of unsaturated quinolizidinone and indolizidinone frameworks.
Asymmetric heck reaction of alkenyl iodides in the presence of silver salts. Catalytic asymmetric synthesis of decalin and functionalized indolizidine derivatives
Decalin derivatives3 (up to 80% ee) and indolizidine derivative 6 (up to 86% ee) have been synthesized by an asymmetric Heck reaction starting with prochiral alkenyl iodides 1 and 4, respectively. The important role of silver salts in the asymmetric Heck reaction is discussed, and the conversion of 6 to δ-coniceine (24) is also described.