Nucleophilic attacks on carbon–carbon double bonds. Part XX. Reaction of active methylene compounds with electrophilic olefins. Formation of substituted 2-amino-4-cyano-4H-pyrans
作者:Zvi Rappoport、David Ladkani
DOI:10.1039/p19740002595
日期:——
Reactions of active methylene compounds with several electrophilic olefins are initiated by a nucleophilic attack on the double bond and the following reaction types have been observed. (a) Base-catalysed reaction of malononitrile with 1,1-dinitro-2,2-diphenylethylene gives ‘diphenylmethylene transfer’ forming 1,1-dicyano-2,2-diphenylethylene. (b) Addition of acetylacetone to tetracyanoethylene (IX)
活性亚甲基化合物与几种亲电烯烃的反应是通过对双键的亲核攻击而引发的,已观察到以下反应类型。(a)丙二腈与1,1-二硝基-2,2-二苯基乙烯的碱催化反应产生“二苯基亚甲基转移”,形成1,1-二氰基-2,2-二苯基乙烯。(b)将乙酰丙酮加至四氰基乙烯(IX)和2,3-二氰基富马酸酯二乙酯(X)或将二甲酮加至(X)得到非环状迈克尔加合物3-(1,1,2,2-四氰基乙基)戊烷-2,4-二酮(XIII),2,3-二氰基-2-二乙酰甲基琥珀酸二乙酯(XX)和2,3-二氰基-2-(4,4-二甲基-2,6-二氧代环己基)琥珀酸二乙酯(XXII) ), 分别。(c)非催化加成几种活性亚甲基化合物(IX)或(X)给出取代的2-氨基-4-氰基-4- ħ -pyrans。由于(XIII)和(XXII)的非催化环化产生4 H-吡喃衍生物,这可能是由开放加合物的环化形成的。(d)蒽酮与(IX)和(X)的反应得到10-