The Endocyclic Restriction Test: Investigation of the Geometries of Nucleophilic Substitution at Phosphorus(III) and Phosphorus(V)
作者:Michael B. Tollefson、James J. Li、Peter Beak
DOI:10.1021/ja961375g
日期:1996.1.1
to alkoxy phosphine 8, of lithio phosphinite 2 to alkoxy phosphine 9, of lithio phosphinate 3 to alkoxy phosphine oxide 10, and of lithio phosphinite borane 4 to alkoxy phosphine borane 11 proceed in an intramolecular fashion. The transfers of stereogenic phosphorus in the conversions of lithio phosphinite (R)-5 to alkoxy phosphine (R)-12, of lithio phosphinate (S)-6 to alkoxy phosphine oxide (S)-13
在内环限制性试验下使用了双标记,以表明在将亚膦酸锂 1 转化为烷氧基膦 8、将亚膦酸锂 2 转化为烷氧基膦 9、将硫代次膦酸锂 3 转化为烷氧基氧化膦 10 时,磷从氧转移到碳和锂硫次膦硼烷 4 到烷氧基膦硼烷 11 以分子内方式进行。在锂硫次膦酸 (R)-5 转化为烷氧基膦 (R)-12、转化锂次膦酸 (S)-6 转化为烷氧基氧化膦 (S)-13 和转化锂硫次膦酸硼烷 (R) 中立体磷的转移)-7 到烷氧基膦硼烷 (R)-14 继续保留磷的立体化学。这些结果排除了这些磷的内环转移的经典串联 SN2 途径和几何等效的串联添加 - 消除途径。磷上这些亲核取代的最可能途径是最初的顶端亲核攻击,然后是假旋转和电...