Ungewoehnlich koordinierte Phosphorverbindungen XXIV. Methylidinphosphan (HCP), ein neuer Cycloadditionspartner fuer 1,3-Dipole

Article abstract of DOI:10.1016/0022-328X(88)80006-8

Methylidynephosphane (2) is generated under flash pyrolytic conditions by cleavage of isobutene from the phosphaalkyne (1) or by elimination of hydrogen chloride from dichloromethylphosphine (3).It undergoes <3+2>-cycloaddition reactions with stable dipoles eq. diazo compounds (2+4a,b->5a,b), methyl azide (2+7->8), benzonitriloxide (2+10->12, 1:2-adduct) and 3-methyl-2,4-diphenyl-1,3-oxazolium-5-olate (2+13->15) to give the corresponding phospholes.Silylated phosphaalkene (19) can be used as a synthetic substitute for 2: the 5-trimethylsilyl-1H-1,2,4-diazaphospholes (22), which result from the reaction of 19 and the diazo compound 4 with chlorotrimethylsilane elimination, are desilylated to 5 by potassium fluoride in dimethyl formamide.