(DI-TERT-BUTYLMETHYLSILYL)AMIDE - A BUILDING-BLOCK FOR AZASILACYCLOBUTANE SYNTHESIS

Di-tert-butylmethylsilylamide reacts with n-BuLi to give the tetrameri c lithium di-tert-butylmethylsilylamide 1. Reactions of lithium (di-te rt-butylmethylsilyl)amide 1 with SiF4 give the mono- (2), bis- (3), tr is- (4), and tetrakis- (5) -[(di-tert-butylmethylsilyl)amino]silanes. Lithiated 3 reacts with Me(3)SiCl to form (di-tert-butylmethylsilyl-tr imethylsilyl butylmethylsilyl)amino-difluorosilane (6); the 1,3-diaza- 2,4-disilacyclobutane 7 is obtained by LiF elimination. The Lithium de rivative of 6 (compound 8) crystallizes with formation of a (SiFNLi) f our-membered ring system. The F-19-NMR spectrum proves that the Li-F b ond fluctuates in solution. Reactions of 1 with (Me(3)Si)(2)C(SiF3)(2) afford different products (9, 10) by controlling the reaction sequenc e. An excess of 1 reacts to give a four-membered CSi2N ring system, th e ylmethylsilyl)-2,4-bis-[(di-tert-butylmethylsilyl) ,4-difluoro-3-bis (trimethylsilyl)-1-aza-2,4-disila cyclobutane (9), disubstitution with formation of bis[(di-tert-butylmethylsilyl)- butylmethylsilyl) amino difluorosilyl] bis (trimethylsilyl) methane (10) occurs in a molar rat io of 2:1. The cyclodisilazane 11 is obtained from dilithiated 10 in a n intramolecular interconversion reaction. The crystal strucutres of 1 , 8, 9, and 11 are reported.