| Popis: |
Methods of preparation of butadienylplumbanes or -stannanes by reactions of vinylacetylene (1-buten-3-yne) with alkyllead and alkyltin hydrides are described. A procedure was developed for in situ butadienylation by addition of lithium aluminum hydride to a mixture of alkylmetal halide and 1-buten-3-yne. In a similar fashion butenylation by addition to 1-butyne was developed. Tripropyl(1-buten-1-yl)tin, triphenyl(1-buten-1-yl)tin, tripropyl(1,2-butadien-1-yl)tin, triphenyl(1,2-butadien-1-yl)tin, dibutyl(di-1-buten-1-yl)tin, triethyl(1-buten-1-yl)lead, and triethyl(1,3-butadien-1-yl)lead have been prepared. In all cases, the organometal hydride adds to 1-butyne as one would predict if a free radical mechanism were operative, i.e., via anti-Markovnikov addition. The organotin hydrides add in a 1,4-manner to vinylacetylene forming allenic derivatives while the organolead hydride adds to vinylacetylene to give the 3,4-addition product. The latter may be formed by 1,4-addition followed by rearrangement. |
