[2-BIS(TRIFLUOROMETHYL) BORANE, (CF3)(2)BNME(2), WITH NITRILE OXIDES,NITRONES AND ME(2)C=SO2 - CRYSTAL AND MOLECULAR-STRUCTURE OF (CF3)(2)B-NME(2)-(T)BUC=N-O AND (CF3)(2)B-NME(2)-CME(2)-S(=O)-O(3]CYCLOADDITION REACTIONS OF DIMETHYLAMINO)

Dimethylamino-bis(trifluoromethyl)borane, (CF3)(2)BNMe(2) (A), undergo es [2 + 3] cycloaddition reactions with various 1,3 dipolar species to yield five-membered heterocycles. While nitrile oxides RCNO give (CF3 )(2)B-NMe(2)-RC=N-O; R = Mes (I), Ph (II), (ClC6H4)-Cl-P (III) (t)Bu ( IV), Pr-i (V), nitrones R(1)HC=N(R(2))-O furnish the thermally less st able and moisture sensitive heterocycles (CF3)(2)B-NMe(2)-R(1)HC-NR(2) -O; R(2) = Me, R(1) = Ph (VI), (ClC6H4)-Cl-P (VII), C6F5 (VIII), (t)Bu (IX), Pr-i (X); R(2) = R(1) = Ph (XI). Analogously, Me(2)C=SO2 yields the five-membered ring (CF3)(2)B-NMe(2)-CMe(2)-S(=O)-O (XII). The con stitution of the novel boron compounds has been deduced from multinucl ear NMR, IR and mass spectra. The structures of IV and XII have been i nvestigated by single-crystal X-ray diffraction.