Substituent effect on the transition from ionic to covalent bonding in triphenylphosphonium ylide derivatives: reactivity of 3-methyl-2,2,2-triphenyl-2H-cyclohepta[d][1,2λ5]oxaphosphole with heterocumulenes
作者:Shin-ichi Naya、Makoto Nitta
DOI:10.1039/b109076n
日期:2002.4.29
X-Ray crystal analysis of 3-methyl-2,2,2-triphenyl-2H-cyclohepta[d][1,2λ5]oxaphosphole [and the triphenylphosphonium ylide] 1a and its parent compound 1b has been carried out. The 31P and 13C NMR spectral studies of 1a,b and their derivatives 1c,d, and the correlation of their chemical shifts with P1âO1 bond lengths obtained by X-ray analyses for 1aâd were investigated to clarify that compounds 1aâd exist as resonance hybrids of a PâO bonding oxaphosphole structure (structure A) and a phosphonium ylide structure (structures B and C). The contribution of the structure A
decreases gradually in the order of 1a > 1c > 1b > 1d in the solid state. On the basis of a linear correlation between P1âO1 bond lengths and θsum (the sum of bond angles between the equatorial bonds), it is clarified that an increase of the P1âO1 bonding character causes change in the configuration of the phosphorus atom from a tetrahedral to a trigonal bipyramidal arrangement. In connection with these studies, inspection of the structure of a related compound, 2,2,2-triphenyl-6,11-methano-2H-cycloundeca[d][1,2λ5]oxaphosphole structure 2, was also carried out. With a view to clarifying the reactivity of 1a in connection with a contribution of canonical
structures A, B, and C, compound 1a was allowed to react with phenyl isocyanate, diphenylcarbodiimide, and phenyl isothiocyanate to give heteroazulenes. The reaction pathways depending on the contribution of canonical structures A, B, and C are discussed.
对 3-甲基-2,2,2-三苯基-2H-环庚[d][1,2δ5]氧杂磷[和三苯基鏻叶立德] 1a 及其母体化合物 1b 进行了 X 射线晶体分析。研究了 1a、b 及其衍生物 1c、d 的 31P 和 13C NMR 谱研究,以及通过 X 射线分析获得的 1a–d 的化学位移与 P1–O1 键长的相关性,以澄清化合物 1aâ d以P–O键合的氧杂磷结构(结构A)和磷叶立德结构(结构B和C)的共振杂化物形式存在。结构A的贡献
固态时按 1a > 1c > 1b > 1d 的顺序逐渐减小。根据P1-O1键长与αsum(赤道键之间的键角之和)之间的线性相关性,可以明确P1-O1键合特性的增加会导致磷原子从四面体排列变为三角双锥排列。与这些研究相关,还检查了相关化合物 2,2,2-三苯基-6,11-methano-2H-cyclooundeca[d][1,2λ5]oxaspire 结构 2 的结构。为了澄清 1a 的反应性与规范的贡献有关
结构A、B和C,使化合物1a与异氰酸苯酯、二苯基碳二亚胺和异硫氰酸苯酯反应,得到杂薁蓝烯。讨论了取决于规范结构 A、B 和 C 的贡献的反应途径。