Phosphorinane and Enol Rings in One Molecule. Evidence for Reciprocal Stabilization of Half-Chair Conformations
作者:Alexander M. Polozov、Alexander V. Khotinen、Eugene N. Klimovitskii
DOI:10.1080/10426509608545220
日期:1996.1
parameters for the axial-equatorial conformational and keto-enol equilibriums were obtained from 1H, 31P NMR and IR measurements in comparison with the planar 4,6-dimethyl isomer (1) containing equatorially oriented enol ring. The X-ray single crystal structure of 5,5-dimethyl-2-(methoxycarbonyl-3′-oxo-2′-butyl)-2-oxo-1,3,2-dioxaphosphorinane (3) reveals the unusual half-chair conformation of the dioxaphosphorinane
摘要。2-(2',4'-dioxo-3'-pentyl)-5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinane (2) 的 X 射线晶体结构显示出显着的半椅畸变轴向的 cisenol 环。分子也经历面内变形。烯醇部分中的 R(O...O) = 2.410 A 表示非常强的氢键。与含有赤道取向烯醇环的平面 4,6-二甲基异构体 (1) 相比,轴向-赤道构象和酮-烯醇平衡的烯醇含量、δOH 和热力学参数通过 1H、31P NMR 和 IR 测量获得。5,5-二甲基-2-(甲氧基羰基-3'-氧代-2'-丁基)-2-氧代-1,3,2-二氧杂膦烷 (3) 的 X 射线单晶结构揭示了不寻常的半椅二氧杂膦环的构象设置了反式烯醇环取代基。1小时,