Spiroheterocycles via Regioselective Cycloaddition Reactions of Nitrile Oxides with 5-Methylene-1H-pyrrol-2(5H)-ones
作者:Nicola J. Beattie、Craig L. Francis、Andris J. Liepa、G. Paul Savage
DOI:10.1071/ch09479
日期:——
Substituted 5-methylene-1H-pyrrol-2(5H)-ones underwent a 1,3-dipolar cycloaddition reaction with nitrile oxides to give the corresponding spiro heterocycles. Critical to this reaction was the development of a biphasic system for base-induced dehydrohalogenation of hydroximoyl chlorides, to give nitrile oxides, in the presence of a base-sensitive dipolarophile. A substituted N-tolyl 5-methylene-1H-pyrrol-2(5H)-one
取代的5-亚甲基-1 H-吡咯-2(5 H)-与腈类化合物进行1,3-偶极环加成反应,得到相应的螺杂环。该反应的关键是在碱敏感的双极性亲和剂的存在下,开发一种双相体系,用于碱诱导的羟肟基氯的脱氢卤化反应,生成腈氧化物。取代的N-甲苯基5-亚甲基-1 H-吡咯-2(5 H)-表现出阻转异构现象,这反过来导致在环加成反应中4:1的面部选择性。