SYNTHESIS OF TRIAFULVALENE PRECURSORS BY CARBENE-DIMERIZATION OF 1-HALOGENO-1-LITHIOCYCLOPROPANES

Synthesis of Triafulvalene Precursors by 'Carbene-Dimerization' of 1-H alogeno-1-lithiocyclopropanes Bi(cyclopropylidenes) 7a, 7c, and 7e are available in a simple one-per reaction by treating 1,1-dibromocyclopr opanes 5 at -95 degrees with BuLi and CuCl2. Attempts towards triafulv alene precursors with good leaving groups are reported. The most promi sing attempt makes use of -3,3'-bis(trimethylsilyl-1,1'-bi(cyclopropyl idene) (7c) which has been oxidized to give the bis(phenylsulfonyl) de rivative 7g. So far, F--induced elimination experiments with 7g failed .