in tetrahydrofuran under inert atm. soln. NaBAr4 in THF was added dropwise at room temp. toBi(III) carboxylate in the same solvent and refluxed for 16 h; solvent was removed in vacuo, residue was extd. into hexane, filtered and subjected to column chromy. on silica (pentane-CH2Cl2 90:10);
