BORON-COMPOUNDS .99. ORGANOSUBSTITUTED CBOSICCN-BICYCLIC AND OPBC = CSI-MONOCYCLIC COMPOUNDS FROM 2,5-DIHYDRO-1,2,5-OXASILABORATOLATES

The potassium salts of the cyclic anions of Activated OSi(CH3,R)C(R') = C(C2H5)B(C2H5)2 (A: R, R' = CH3; B: R = C2H5, R' = CH3; C: R = C6H5, R' = CH3 react with [(CH3)2NCH2]Br in THF to yield the bicyclic compounds (C2H5)2C Activated B(C2H5)OSi-(CH3,R)C(R')CH2N(CH3)2: 1a (X-ray crystal structure analysis), 1b/1b' (endo/exo-C2H5), and 1c/1c' (endo/exo-C6H5). D (R = CH3, R' = C6H5) reacts with [(CH3)2NCH2]Br to form a 1:4 mixture of 1d together with the heterocycle Activated OSi(CH3)2-C(C6H5) = C(C2H5)B(C2H5) (3d) with elimination of (CH3)2N-C3H7. - From A - D and ClP(C6H5)2 the six-membered heterocycles Activated OP(C6H5)2B(C2H5)2C(C2H5) = C(R')Si(CH3,R) (2a - d) are obtained in yields of ca. 90%.