Synthesis of 1,2-bis(1-boraadamant-2-yl)ethane derivatives. Crystal structure of the racemic form

Condensation of triallylborane with octa-1,7-diyne followed by treatment of the reaction mixture with methanol afforded a mixture of stereoisomeric 1, 4-bis(3-methoxy-3-borabicyclo[3.3.1]non-6-en-7-yl)butanes (1a,b). Hydrobora tion of the latter with a solution of BH3 in THF yielded the tetrahydrofura n complex of 1,2-bis(1-boraadamant-2-yl)ethane (2) as a mixture of diastere omers. Pure racemate (2a) was obtained by crystallization from the reaction mixture and it was converted into the pyridine complex of 1,2-bis(1-boraad amant-2-yl)ethane (3). The structure of the latter was established by X-ray diffraction analysis. Complex 2a was converted into the corresponding race mic 1,2-bis(1-hydroxyadamant-2-yl)ethane (4a) by the carbonylation -oxidati on reaction.