Highly Regioselective α-Addition of Alkynyl and Alkenyl Grignard Reagents to 1-Alkoxycarbonylpyridinium Salts and Its Application to Synthesis of 1-Azabicycloalkanes and (±)-Solenopsin A
作者:Ryohei Yamaguchi、Yutaka Nakazono、Toshitsugu Matsuki、Ei-ichiro Hata、Mituyosi Kawanisi
DOI:10.1246/bcsj.60.215
日期:1987.1
Nucleophilic addition of a variety of alkynyl and alkenyl Grignard reagents to 1-methoxycarbonylpyridinium chloride takes place at the α-position in a highly regioselective manner to give 2-substituted 1-methoxycarbonyl-1,2-dihydropyridines exclusively, while, with alkyl Grignard reagents, a lack of the regioselectivity is observed. These results may be explained by the HSAB principle. The high α-regioselectivity
各种炔基和烯基格氏试剂与 1-甲氧基羰基氯化吡啶的亲核加成以高度区域选择性的方式在 α-位发生,以专门产生 2-取代的 1-甲氧基羰基-1,2-二氢吡啶,而使用烷基格氏试剂,观察到缺乏区域选择性。这些结果可以用 HSAB 原理来解释。在 2-取代吡啶的情况下也保持了高 α-区域选择性,仅得到 2,6-二取代的 1,2-二氢吡啶,其可以立体选择性地转化为顺式和反式 2,6-二烷基化哌啶。1-甲氧羰基吡啶鎓盐的这些高度区域选择性的α-炔基化被用于合成1-氮杂双环烷烃和(±)-solenopsin A。