GaCl3-assisted [3+2] cycloaddition: A route to new binary PN-heterocycles

Starting from a [3+2] synthetic tool kit, new PN-heterocycles may be isolated according to a new synthetic approach called GaCl3-assisted [3+2] cycloaddition. According to this concept the dipolarophile Mes∗–Ndouble bond; length as m-dashP–Cl (Mes∗ = 2,4,6-tri-tert-butylphenyl) was reacted with the 1,3-dipole (TMS)2N–N(TMS)–PCl2 (TMS = trimethylsilyl) yielding the kinetically stabilized [3+2] cycloaddition product triazadiphosphole, Mes∗N3P2, stabilized as GaCl3 adduct. Synthesis, structure and bonding are discussed.