Synthesis of distibiranes and azadistibiranes by cycloaddition reactions of distibenes with diazomethanes and azides

Cycloaddition reactions of distibene [L(Me(2)N)GaSb](2) (L = HC[C(Me)NDipp](2); Dipp = 2,6-i-Pr(2)C(6)H(3))[double bond, length as m-dash] with a series of organoazides RN(3) (R = Ph, p-CF(3)Ph, 1-adamantyl (ada)) yielded azadistibiranes [L(Me(2)N)GaSb](2)NR (R = Ph 1, p-CF(3)Ph 2, ada 3), whereas Me(3)SiN(3) reacted with insertion into one Ga–Sb bond and formation of L(Me(2)N)GaSbSb(NSiMe(3))Ga(NMe(2))L (4). Analogous compounds 5 and 6 formed after heating of 1 and 2 above 60 °C. Prolonged heating of 5 resulted in a [2 + 2] cycloaddition accompanied by elimination of LGa(NMe(2))(2) and formation of tetrastibacyclobutane 7, while the reaction of 5 with a second equivalent of PhN(3) gave heteroleptic azadistibirane 9, which isomerized at elevated temperature to distibene 10. Cycloaddition also occurred in reactions of [L(X)GaSb](2) (X = NMe(2), OEt, Cl) with Me(3)Si(H)CN(2), yielding distibiranes [L(X)GaSb](2)C(H)SiMe(3) (X = NMe(2)11, OEt 12, Cl 13). Compounds 1–13 were characterized by IR, UV-Vis and NMR spectroscopy and sc-XRD. The mechanism of the reaction of [L(Me(2)N)GaSb](2) with PhN(3) and Me(3)SiN(3) and the electronic nature of the resulting compounds were studied by DFT calculations.