Cycloaddition reactions of 1-Alkyl-3,4,5-triphenyl-1,2-iphosphacyclopenta-2,4-dienes in the coordination sphere of tungsten carbonyl

1-Alkyl-3,4,5-triphenyl-1,2-diphosphacyclopenta-2,4-dienes react with tungsten hexacarbonyl under the conditions of “indirect” replacement of the carbonyl group to give 1: 1 complexes; [4+2] cycloaddition reactions of these complexes with maleic acid derivatives and substituted acetylenes afford tungsten carbonyl complexes containing 10-alkyl-1,10-diphosphatricyclo[5.2.1.0 2.6 ]deca-8-ene-3,5-diones and 1-alkyl-2,3-diphenylphosphirenes, respectively.