(Z)-3-(Diethylboryl)-2-(trimethylsilyl)-2-pentene, obtainable from Na triethyl-1-propynylborate and ClSiMe3, reacts with alk. metal amides MNH2 (M = Na, K) with elimination of methane to give the alk. metal 4,5,5-triethyl-2,5-dihydro-2,2,3-trimethyl-1,2,5-azoniasilaboratoles (I). On warming, I eliminate ethane to form 1-alk. metal 4,5-diethyl-2,5-dihydro-2,2,3-trimethyl-1,2,5-azasilaboroles (II). II (metal = Na) reacts with RCl to give III (R = SiMe3, GeMe3, GePh3, SnMe3, NHMe, NHPh, PPh3, AsPh3, BEt3, BC7H14). Transamination of III (R = Me) (IV) with RNH2 or H2NXNH2, gave III (R = n-octyl, PhCH2, Ph, o-H2NC6H4) or V [X = (CH2)2, (CH2)6, p-C6H4]. Also, IV and R1NHNH2 (R1 = Me, Ph) gave III (R = R1NH) and VI (R2 = R1, R3 = H; R2 = H, R3 = R1). The crystal structure of VII was detd.