in tetrahydrofuran under N2, 24 h stirring at reflux, cooled to 25°C,quenched with MeOH, pptn. by addn. of heptane; filtered, freed of volatike solvent, dark residue redigested with warm heptane, filtered, solvent removal, recrystn. from acetonitrile and charcoal, repeated recrystn. from CH3CN-CH2Cl2, elem. anal.;

n-butyl lithium in not given treatment of mesithylethyne with n-BuLi, react. with fluoro(dimesityl)borane;

1: tetrahydrofuran 2: tetrahydrofuran View Scheme

1: toluene 2: O2 / toluene View Scheme