Novel Syntheses of α,β-Unsaturated Esters, α,β-Unsaturated γ-Lactones, and 2-Alkoxypyrroles <i>via</i> 1,2,4-Triazole-Stabilized Allenic Anions
作者:Alan R. Katritzky、Daming Feng、Hengyuan Lang
DOI:10.1021/jo961397l
日期:1997.2.1
phenylpropargylaldehyde diethyl acetal 8 and 1,2,4-triazole) reacts with alkyl halides, aldehydes, ketones, and alpha,beta-unsaturated ketones to give exclusively gamma-substituted allenic products of type 10. These adducts underwent mild in situ hydrolysis enabling convenient syntheses of alpha,beta-unsaturated esters 9a-c and alpha,beta-unsaturated gamma-lactones 16, 18, 20, and 22. Reactions of dianion 13 with
1-(1,2,4-三唑-1-基)苯基炔丙基乙基醚11(由苯基炔丙基醛二乙基乙缩醛8和1,2,4-三唑制备)的二价阴离子12(左叉的右叉)烷基卤化物,醛,酮和α,β-不饱和酮,仅得到类型10的γ-取代的烯丙基产物。这些加合物经过温和的原位水解,可方便地合成α,β-不饱和酯9a-c和α,β -不饱和的γ-内酯16、18、20和22。二价阴离子13与亚胺的反应以高收率生成了1,3,4-三取代的2-烷氧基吡咯27、30和31。烷基取代的类似物34经历类似的反应,主要得到γ产物39,40和42以及一小部分α-类似物。