Super Acid-Induced Pummerer-Type Cyclization Reaction: Improvement in the Synthesis of Chiral 1,3-Dimethyl-1,2,3,4-tetrahydroisoquinolines
作者:Toshiaki Saitoh、Kentaro Shikiya、Yoshie Horiguchi、Takehiro Sano
DOI:10.1248/cpb.51.667
日期:——
Improved synthesis of four stereoisomeric chiral 1,3-dimethyl-1,2,3,4-tetrahydroisoquinolines (1a, b, ent-1a, b) was achieved via the super acid-induced cyclization of chiral N-[1-methyl-2-(phenylsulfinyl)ethyl]-N-(1-phenylethyl)formamides (4a, b, ent-4a, b) using the Pummerer-type cyclization reaction as a key step. The cyclization leading to the isoquinoline ring proceeded in a quantitative manner
通过超强酸诱导的手性N- [1-甲基-使用Pummerer型环化反应作为关键步骤,制得2-(苯亚磺酰基)乙基] -N-(1-苯乙基)甲酰胺(4a,b,ent-4a,b)。当使用三氟甲烷磺酸(TFSA)作为过酸时,导致异喹啉环的环化以定量方式进行,尽管4-苯硫基TIQ衍生物(5)的Friedel-Crafts型烷基化以苯为溶剂伴随着环化得到4-苯基-TIQ(7)。当使用大量过量的TFSA时,仅形成副产物(7)。