Cyclisation reactions of 2-substituted benzoylphosphonates with trialkyl phosphites via nucleophilic attack on a carbonyl-containing ortho substituent
作者:Yuen-Ki Cheong、Philip Duncanson、D. Vaughan Griffiths
DOI:10.1016/j.tet.2008.01.012
日期:2008.3
and dimethyl 2-benzoyloxy-benzoylphosphonate undergo cyclisation and deoxygenation in the presence of excess trimethyl phosphite to give dimethyl (3-methyl-1-benzofuran-2-yl)phosphonate and dimethyl (3-phenyl-1-benzofuran-2-yl)phosphonate, respectively. The reaction pathway has been shown to involve phosphite attack on initially formed tricyclic dioxaphospholane intermediates with the subsequent loss
在过量亚磷酸三甲酯的存在下,对2-乙酰氧基-二甲基和2-苯甲酰氧基-苯甲酰基膦酸二甲酯进行环化和脱氧,得到(3-甲基-1-苯并呋喃-2-基)膦酸二甲酯和(3-苯基-1-苯并呋喃二甲基)二甲酯。 -2-基)膦酸酯。已显示该反应途径涉及亚磷酸酯对最初形成的三环二氧杂膦烷中间体的攻击,随后损失了两个分子的磷酸三甲酯。在不存在额外的亚磷酸三甲酯的情况下,最初形成的三环二氧杂膦烷中间体会损失一个分子的磷酸三甲酯,然后进行新的重排以生成β-酮膦酸酯。该反应的机理有助于解释一些先前报道的环氧化物重排。相比之下,