Reactions of heterocumulenes with organometallic reagents: XXII. Quantum chemical study of structural transformations of benzylsulfanyl-substituted 2-aza-1,3,5-triene by the action of superbases. Concurrent formation of 4,5-dihydro-3H-azepine and 4,5-dihydro-1,3-thiazole

摘要

The formation of 4,5-dihydro-3H-azepine and/or 4,5-dihydro-1,3-thiazole structures in the reaction of 1-(benzylsulfanyl)-2-methoxy-N-(propan-2-ylidene)buta-1,3-dien-1-amine (2-aza-1,3,5-triene) with potassium tert-butoxide or lithium diisopropylamide has been analyzed by B3LYP/6-31G(d,p) quantum chemical calculations. According to the calculations, the reaction with potassium tert-butoxide gives 4,5-dihydro-3H-azepine and 4,5-dihydro-1,3-thiazole derivatives with almost equal probabilities, whereas lithium diisopropylamide clearly favors the formation of thiazole ring.