Reactions of (CF3)2BNMe2 with Grignard and related reagents. Crystal and molecular structure of (CF3)(Mes)FB-FC=NMe2 and Ph3P-CH2-(CF3)2B-NMe2 1

Article abstract of DOI:10.1016/S0022-328X(96)06400-5

Dimethylaminobis(trifluoromethyl)borane, (CF₃)₂BNMe₂ (A), reacts with Grignard reagents RMgBr to yield, after hydrolysis, the dimethylamine boranes R(CF₃)₂B · NHMe₂ (R = Me (I), Et (II), ⁱPr (III), -CH₂CH=CH₂ (IV), Ph (V), ^pTol (VI), ^oTol (VII), ^pClC₆H₄ (VIII) and -C≡CH (IX)). Alkynyltrimethylstannanes Me₃Sn-C≡C-R (R = Ph, ⁿBu) add to A across the B=N double bond and yield (R-C≡C)(CF₃)₂B · NMe₂SnMe₃, the hydrolysis of which gives (Ph-C≡C)(CF₃)₂B · NHMe₂ (X) and (ⁿBu-C≡C)(CF₃)₂B · NHMe₂ (XI) respectively. In contrast, mesitylmagnesiumbromide reacts with A to yield (CF₃)(Mes)FB-FC=NMe₂ (XII), hydrolysis of which furnishes (CF₃)(Mes)FB-C(=O)NHMe₂ (XIII). Of the phosphorus ylids, only Ph₃P=CH₂ and Ph₃P=CHCH₃ react with A to give the respective adducts Ph₃P-CH₂-(CF₃)₂B-NMe₂ (XIV) and Ph₃P-CH(CH₃)-(CF₃)₂B-NMe₂ (XV). CF₃SO₃CH₃ alkylates XIV at the nitrogen atom to form [Ph₃P-CH₂-(CF₃)₂B-NMe₃]₊[CF₃SO₃]_- (XVI). The crystal and molecular structures of XII and XIV have been determined by X-ray methods.