3-BOROLENES WITH DIASTEREOTOPIC FACES - S YNTHESIS OF MINO)-4-BORATRICYCLO[5.2.1.0](2),(6)]DEC-2(6)-ENES AND STRUCTURE OF THE DIMETHYLAMINODERIVATIVE

Two syntheses of 2,5-dihyro-1H-borole derivatives with diastereotopic faces are described. 2,3-Dimethylenenorbornane (2) is transformed into the zirconocene complex 5 (= CP2Zr . 2) in a large-scale preparation; 5 reacts with dichloro-(dialkylamino)boranes BC12(NR2) to give ylamin o)-4-boratricyclo[5.2.1.0(2,6)]dec-2(6)-enes 1 (R = Me, iPr). Alternat ively, 2,3-dimethylnorbornene (santene) (3) or 3-methyl-2-methylenenor bornane (4) can be kaliated by means of Lochmann-Schlosser base to giv e a dimetallation product 6 (= K2 . 2); treatment of 6 with BC12(NR2) also affords the boratricycles 1 (R = Et, iPr). The structure of the d imethylamino derivative la has been determined by X-ray diffraction.