Studies on Sterically Protected Multiple Bonding Involving Low Coordinated Phosphorus Atoms

通过利用2，4，6-三叔丁基苯基(这里简称Ar基)作为保护基团，制备了含有低配位状态的特殊化合物的空间保护的磷。分离得到了一些特殊的有机磷化合物，如二膦(-P=P-)、1，3-二磷杂烯(-P=C=P-)和具有配位数2或1的低配位磷原子(S)的磷杂炔(-C*P)，它们是动力学稳定的化合物。尝试合成了含有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-octahydro-1，1，4，4，5，5，8，8-octamethyl-9-anthryl，和2，4-二叔丁基-6-二甲氨基苯基的双膦化合物。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，也可用作双膦和不对称双膦的保护助剂。发展了一种1，3-二磷烯的制备方法，该方法通过二氯卡宾与双膦的加成反应生成二氯二膦，再用适当的烷基锂试剂转化为二磷。该方法已成功地以不对称双膦为起始原料制备了一些不对称双磷烯。用这种方法成功地制备了磷杂丁三烯(-P=C=C=C)和二磷杂丁三烯(-P=C=C=P-)等扩展的磷丁三烯。发展了一种新的磷杂炔的制备方法，包括1-氯-2-磷代亚乙基锂的消除和分子内重排，并进行了核磁共振研究，试图观察在这种不寻常的重排反应中异腈的磷类似物的中间体。

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.