in tetrahydrofuran under Ar or N2, dropwise addn. of trimethyl borate to the soln. of Li compd. at -78°C over a period of 1 h with stirring, stirred overnight as the mixt. warmed to 20°C,; concd. under vac., residue treated with 85 percent phosphoric acid and ice, extd. with ether, washed with water, concd. under vac., recrystd. from moist ether/petroleum ether, elem.anal.;

in diethyl ether

pinacol hydrate in diethyl ether under Ar or N2, equimolar amt. of educts; phases sepd., ether phase washed with water, dried over MgSO4, distd., may be kept indefinitely as a liq., cooled to -78°C and scratching induced crystn., elem.anal.;

1: diethyl ether 2: (i) LDA, THF, (ii) /BRN= 969135/ View Scheme

1: diethyl ether 2: (i) LDA, Me2NCH2CH2NMe2, THF, (ii) /BRN= 1740743/ View Scheme