Divergent approach to the synthesis of (-)-balanol heterocycle and cis-3-hydroxypipecolic acid based on chiral 2-aminoalkanol equivalent
作者:Subhash P. Chavan、Dinesh B. Kalbhor、Rajesh G. Gonnade
DOI:10.1016/j.tet.2020.131773
日期:2021.1
Enantioselective synthesis of the hexahydroazepine core of (−)-balanol and formal synthesis of cis-3-hydroxypipecolic acid from a common intermediate have been accomplished by a divergent path. The common intermediate was accessed from a favorably protected enantiomerically pure 2-amino-1,3,4-butanetriol (ABT) equivalent via oxidation and Wittig olefination. The synthesis of (−)-balanol heterocycle
(-)-balanol的六氢氮杂core核的对映选择性合成和从共同的中间体形式顺式-3-羟基哌酸的正式合成已通过一条不同的途径完成。常见的中间体是通过氧化和维蒂希烯化反应从对映体纯的2-氨基-1,3,4-丁三醇(ABT)等效物中得到良好保护的。(-)-balanol杂环的合成具有串联还原/缩醛脱保护/γ-内酯化反应和一锅叠氮化物还原,随后形成七元氮杂杂环的趋势,而顺式-3-羟基哌酸的路线突出了碱基诱导哌啶环的形成和区域选择性苄基乙缩醛的裂解。