Generation of Tricooordinate Boron Anions and Synthetic Use of Novel Boron Compounds

用磷硼烷研究了三配位硼阴离子的生成和反应。用两个等量的4,4′-二叔丁基联苯锂（LDBB）在四氢呋喃中还原三环己基膦-单碘硼烷。生成的化学物质与多种亲电试剂反应，如氯三甲基硅烷、二苯基二硫化物、三氟甲烷磺酸甲酯、环氧乙烷、苯甲醛、碳酸二乙酯和二氧化碳，生成硼原子上有取代基的膦硼烷。三叔丁基膦-单碘硼烷与LDBB反应，再用水或苄基溴处理，分别得到二叔丁基膦-硼烷或苄基（二叔丁基）膦-硼烷。这些反应清楚地表明生成了三配位硼阴离子作为反应中间体。用三氟甲烷磺酸处理磷硼，合成了硼原子上含有三氟甲烷磺酰氧基的磷硼烷。所得化合物的结构通过单晶x射线分析明确确定。这些化合物与各种亲核试剂（如有机铜试剂）发生亲核取代反应，得到收率较高的b取代膦硼烷。还合成了新的含P-B-S键的杂环化合物，并对其结构和化学性质进行了表征。

The generation and reactions of tricoordinate boron anions have been investigated using phosphine-boranes. Tricyclohexylphosphine-monoiodoboranes were reduced by two equivalents of lithium 4,4'-di-tert-butylbiphenylide (LDBB) in tetrahydrofuran at -78ﾟC.The generated chemical species reacted with a variety of electrophiles such as chlorotrimethylsilane, diphenyl disulfide, methyl trifluoromethanesulfonate, ethylene oxide, benzaldehyde, diethyl carbonate, and carbon dioxide to affordphosphine-boranes possessing a sub stituent at the boron atom. Reaction of tri-tert-butylphosphine-monoiodoborane with LDBB,followed by treatment with water or benzyl bromide, provided di-tert-butylphosphine-borane or benzyl (di-tert-butyl) phosphine-borane, respectively. These reactions clearly indicate that tricoordinate boron anions were generated as the reactive intermediates.Phosphine-boranes possessing trifluoromethanesulfonyloxy group at the boron atom were synthesized by treatment of phosphine-borans with trifluoromethanesulfonic acids. The structures of the obtained compounds were unequivocally determined by single crystal X-ray analyzes. These compounds underwent nucleophilic substitution reaction with various nucleophiles such as organocopper reagents to give B-substituted phosphineboranes in good yields.Novel heterocyclic compounds containing P-B-S linkages were also synthesized, and their structures and chemical properties were characterized.