Reactions of (CF 3) 2BNMe 2 with Grignard and related reagents. Crystal and molecular structure of (CF 3)(Mes)FB [sbnd]FC [dbnd]NMe 2 and Ph 3P [sbnd]CH 2[sbnd](CF 3) 2B [sbnd]NMe 2

Abstract

Dimethylaminobis(trifluoromethyl)borane, (CF 3) 2BNMe 2 ( A), reacts with Grignard reagents RMgBr to yield, after hydrolysis, the dimethylamine boranes R(CF 3) 2B NHMe 2 (R = Me ( I), Et( II), iPr( III), -CH 2CH=CH 2 ( IV), Ph ( V), pTol ( VI), oTol ( VII), pClC 6H 4 ( VIII) and −C CH ( IX)). Alkylnytrimethylstannanes Me 3Sn C C R (R = Ph, nBu) add to A across the B N double bond and yield (R C C)(CF 3) 2B·NMe 2SnMe 3, the hydrolysis of which gives (Ph C C)(CF 3) 2B·NHMe 2 ( X) and ( nBu C C)(CF 3) 2B·NHMe 2 ( XI) respectively. In contrast, mesitylmagnesiumbromide reacts with A to yield (CF 3)(Mes)FB FC NMe 2 ( XII), hydrolysis of which furnishes (CF 3)(Mes)FB C( O)NHMe 2 ( XIII). Of the phosphorus ylids, only Ph 3P CH 2 and Ph 3P CHCH 3 react with A to give the respective adducts Ph 3P CH 2 (CF 3) 2B NMe 2 ( XIV) and Ph 3P CH(CH 3) (CF 3) 2B NMe 2 ( XV). CF 3SO 3CH 3 alkylates XIV at the nitrogen atom to form [Ph 3P CH 2 (CF 3) 2B NMe 3] +[CF 3SO 3] − ( XVI). The crystal and molecular structures of XII and XIV have been determined by X-ray methods.