Enzymatic Route to Chiral, Nonracemic cis-2,6- and cis,cis-2,4,6-Substituted Piperidines. Synthesis of (+)-Dihydropinidine and Dendrobate Alkaloid (+)-241D
摘要:
Piperidine-based compounds are an important class of natural alkaloids found in plants, insects, and amphibians. A general asymmetric synthesis of 2-alkyl-6-methylpiperidines is presented via the enzymatic desymmetrization of meso cis-2,6- and cis,cis-2,4,6-substituted piperidines with Aspergillus niger lipase(ANL). The enzymatic reaction proceeds in excellent chemical yield and high enantiotopic selectivity (ee greater than or equal to 98%). The general method is used to effect the synthesis of (+)-dihydropinidine-HCl as well as the first asymmetric synthesis of dendrobate alkaloid (+)-241D.
Hydrogenation of functionalised pyridines with a rhodium oxide catalyst under mild conditions
作者:Sydney Williams、Leiming Qi、Robert J. Cox、Prashant Kumar、Jianliang Xiao
DOI:10.1039/d3ob01860a
日期:——
Piperidines are one of the most widely used building blocks in the synthesis of pharmaceutical and agrochemical compounds. The hydrogenation of pyridines is a convenient method to synthesise such compounds as it only requires reactant, catalyst, and a hydrogen source. However, this reaction still remains difficult for the reduction of functionalised and multi-substituted pyridines. Here we report the
哌啶是药物和农化化合物合成中使用最广泛的结构单元之一。吡啶的氢化是合成此类化合物的便捷方法,因为它只需要反应物、催化剂和氢源。然而,该反应对于官能化和多取代吡啶的还原仍然很困难。在这里,我们报道了使用稳定的市售铑化合物Rh 2 O 3来还原各种未保护的吡啶。该反应条件温和,底物范围广,具有实用价值。