Abstract
ABSTRACT: The reaction between ((Me,Si),CH) PH(CH2 OMe) (4) and 1 equiv of BH, SMe, yields the phosphine-borane {(Me,Si),CH)PH(BH)(CH-2-OMe) (5). Subsequent reaction between 5 and 1 equiv of n-Buli in THF gives the phosphido- borane complex [[(Me,Si),CH)P(BH) (CH,-2-OMe)] Li(THF) (6a), which was isolated as a colorless microcrystalline solid. Treatment of 5 with 1 equiv of PhCH,M yields the corresponding complexes [{(Me Si),CH)P(BH) (CH-2-OMe)]ML (ML = Na- (THF) (6b), K(pmdeta) (6c); pmdeta N,N,N,N,N"-pentam ethyldiethylenetriamine), after crystallization in the presence of the corresponding coligand. While compounds 6b,c are stable toward heat, compound 6a decomposes on heating to 50 °C in toluene to give the cluster [[[(Me,Si),CH)PH(CH,-2-O)]Li], (7) and the tertiary phosphine-borane ((Me,Si),CH)P(BH,)(Me)(CH-2-OMe) (8). Related C-O cleavage reactions are observed when Mgl, is treated with 2 equiv of 6a and when Cal, is treated with 2 equiv of [[(Me,Si),CH)P(BH) (C,H,-2-OMe)]K in THF, giving [{(Me,Si),CH)P(BH)(CH,-2-O)Mg(THF),]; (9) and [{(Me,Si),CH)P(BH)(CH-2-O) Ca(THF)], (10), respec- tively, along with equiv of 8 in each case. In contrast, the reaction between Sel, and 2 equiv of [((Me,Si),CH)P(BH)(CH-2- OMe)]K in THF yields [[(Me,Si),CH)P(BH,)(C,H,-2-OMe)Sr(THF).] (11).