有机磷化合物的研究 XXV.溶剂性质对烯丙基膦酸酯碳阴离子和芳醛反应区域选择性的影响

Studies on Organophosphorus Compounds XXV. The Effect of Solvents on the Regioselectivity of the Reaction of the Carbanion of Diethyl Allylphosphonate with the Aromatic Aldehydes

杂原子稳定的烯丙基碳阴离子反应区域选择性的研究是一个很活跃的领域。取代烯丙基膦酸二乙酯碳阴离子和醛、酮的反应已有记载。本文研究烯丙基膦酸二乙酯碳阴离子(1)和苯甲醛(2a)、对甲基苯甲醛(2b)的反应,考察溶剂对反应区域选择性的影响。 1和2反应,同时生成α-位反应产物3和γ-位反应产物4。

The reaction of the carbanion of diethyl allylphosphonate(1) with benzaldehyde (2a) and p-methylbenzaldehyde (2b) was reported. A series of solvents with different polarity was employed to study the effect of solvents on the regioselectivity of the reaction. It was observed that the reaction was kinetically controlled. It was also found that the reaction took place predominately on the α-position in THF, and that more γ-substituted product (4) was obtained than the α-substituted product (3) in n- pentane. With the addition of cemplexing agent, such as TMEDA or HMPT, the effect of solvents on the regioselectivity of the reaction decreased. The reaction of 1 with 2 gave only diethyl 4-hydroxyl-trans-phenylbutenyl-1-phosphonate (or diethyl 4- hydroxyl-trans-4′-methylphenylbutenyl-1-phosphonate) under various conditons.