intramolecular cyclization oftrans- andcis-2-allyl-6-R-1,2,3,6-tetrahydropyridines, obtained from pyridine and triallylborane, has been elaborated. The closure of the five-membered ring is carried out by hydroboration-oxidation followed by cyclization of the resulting δ-amino alcohols in the presence of the Ph3P−CBr4−Et3N system. (Pr2BH)2 and Pr3B are used as the hydroborating reagents, and H2O2 in an acid medium
已经详细阐述了基于反式和顺式-2-烯丙基-6-R-
1,2,3,6-四氢吡啶的分子内环化合成 5-取代
吲哚里西啶的一般方法,该方法从
吡啶和
三烯丙基
硼烷中获得。五元环的闭合是通过
硼氢化-氧化然后在 Ph3P-
CBr4-Et3N 系统存在下将所得 δ-
氨基醇环化来进行的。(Pr2BH)2 和 Pr3B 用作
硼氢化试剂,在酸性介质中用
H2O2 氧化形成的 2-[3-(二丙基
硼基]-Δ2-
哌啶。该方法已用于合成两种天然
生物碱类:分别由cis-和trans-2-allyl-6-hexyl-1,2,3,6-tetrahydropiridine制备
吲哚里西啶209D(cis-5-hexylindolizidine)及其反式异构体;