An efficient first approach to the Stemona alkaloid (+/-)-Stemonamine has been developed on the basis of a key TiCl4 promoted tandem Semipinacol rearrangement/Schmidt reaction and a Dieckmann condensation reaction.
Development of the Intramolecular Prins Cyclization/Schmidt Reaction for the Construction of the Azaspiro[4,4]nonane: Application to the Formal Synthesis of (±)-Stemonamine
A TiCl4-promoted tandem intramolecularPrins cyclization/Schmidt reaction has been designed and developed to be an efficient method for the construction of the azaspiro[4,4]nonane. The present tandem protocol has been employed to construct the tricyclic azaquaternary skeleton (ring A, B, and C) of stemonamine.
An efficient first approach to the Stemona alkaloid (+/-)-Stemonamine has been developed on the basis of a key TiCl4 promoted tandem Semipinacol rearrangement/Schmidt reaction and a Dieckmann condensation reaction.
Formal Syntheses of (±)-Stemonamine and (±)-Cephalotaxine
A short and efficient approach to aza-quaternary pyrrolo[1,2-a]azepine 8 and aza-quaternary indolizine 23, as the crucial intermediates for syntheses of stemonamine (1a) and cephalotaxine (1b), has been developed on the basis of the key intramolecular Schmidt reaction of symmetric azido-diones 5 and 18, respectively.
在氮杂-吡咯并[1,2- a ]氮杂8和氮杂-四氮杂吲哚23的短而有效的方法的基础上,已经开发了一种方法,它们是合成stem烯胺(1a)和头孢他辛(1b)的关键中间体。对称叠氮基二酮5和18的关键分子内Schmidt反应。