Studies on Sterically Protected Multiple Bonding Involving Low Coordinated Phosphorus Atoms

利用2,4,6-三-叔丁基苯基（简称Ar基）作为保护基团制备了具有低配位态的特殊化合物的立体保护磷。二磷烯（-P=P-）、1,3-二磷二烯（-P=C=P-）和磷炔（-C*P）等不寻常的有机磷化合物具有配位数为2或1的低配位磷原子，被分离出来并表征为动力学稳定的化合物。除Ar基团以外的保护基团已被开发出来，以利用低配位有机磷化合物的稳定性，如下所示。成功地制备了含有2,6-二叔丁基苯基、2,4,6-三叔戊基苯基、1,2,3,4,5,6,7,8-八氢-1,1,4,4,5,5,8,8-八甲基-9-蒽基和2,4-二叔丁基-6-二甲氨基苯基的二膦。强吸电子基团，如2,4,6-三（三氟甲基）苯基和2,6-二（三氟甲基）苯基，也可用作二膦和不对称二膦的保护助剂。提出了一种制备1,3-二磷二烯的方法，即二氯碳烯与二磷二烯加成反应得到二氯二磷二烯，再用合适的烷基锂试剂将二氯二磷二烯转化为二磷二烯。该制备方法已成功地从不对称二磷烯出发制备了几种不对称二磷烯。用该方法成功制备了磷酸丁三烯（-P=C=C=C）和二磷酸丁三烯（-P=C=C=P-）。本文提出了一种新的制备磷酸烷的方法，通过消除1-氯-2-磷酸乙烯基锂并进行分子内重排，并进行了^<31>P核磁共振研究，试图在这种不寻常的重排反应中观察异腈的磷类似物的中间作用。

Sterically protected phosphorus containing unusual compounds in low coordination states were prepared by utilizing the 2,4,6-tri-t-butylphenyl moiety (here abbreviated to the Ar group) as a protective group. Such unusual organophosphorus compounds as diphosphene (-P=P-), 1,3-diphosphaallene (-P=C=P-), and phosphaalkyne (-C*P) having low coordinated phosphorus atom(s) of coordination number 2 or 1 were isolated and characterized as kinetically stable compounds.Protective groups other than the Ar group have been developed to utilize the stabilization of low coordinated organophosphorus compounds as follows. Attempts to prepare diphosphenes involving 2,6-di-t-butylphenyl, 2,4,6-tri-t-pentylphenyl, 1,2,3,4,5,6,7,8-octahydro-1,1,4,4,5,5,8,8-octamethyl-9-anthryl, and 2,4-di-t-butyl-6-dimethylaminophenyl were successful. Strong electron-withdrawing groups, such as 2,4,6-tris(trifluoromethyl)phenyl and 2,6-bis(trifluoromethyl)phenyl, were also useful as a protective auxiliary of diphosphenes as well as unsymmetrical diphosphenes.A preparative method of 1,3-diphosphaallenes has been developed involving addition reaction of dichlorocarbene to diphosphenes leading to dichlorodiphosphiranes, which were further converted to diphosphaallenes with an appropriate alkyllithium reagent. This preparative method has been successful in preparation of some unsymmetrical diphosphaallenes' starting from unsymmetrical diphosphenes. Attempted preparations of the extended phosphacumulenes such as phosphabutatriene (-P=C=C=C ) and diphosphabutatriene (-P=C=C=P-) have been successful by this method.A new preparative method of phosphaalkynes has been developed involving elimination and intramolecular rearrangement of 1-chloro-2-phosphaethenyllithiums and the ^<31>P NMR studies have been made in an attempt to observe intermediacy of phosphorus analogue of isonitrile during this unusual rearrangement reaction.