SYNTHESIS OF STABLE BORYL-SUBSTITUTED DIAZOMETHANE AND NITRILIMINES

Addition of bis(diisopropylamino)chloroborane to the lithium salt of (triisopropylsilyl)-, [bis(diisopropylamino)phosphino]-, and [bis(diisopropylamino)thioxophosphoranyl]diazomethane led to the corresponding stable N-borylnitrilimines 6-8 in 80, 90, and 95% yield, respectively. Addition of sulfur to C-phosphinonitrilimine 7 gave the thioxophosphoranyl analogue 8. The chloroborane reacted with the lithium salt of diazomethane, leading to a mixture of [bis(diisopropylamino)boryl]diazomethane (11) (54% yield) and bis[bis(diisopropylamino)boryl]nitrilimine (9) (20% yield). Compound 9 can be obtained in good yield by reacting the lithium salt of [bis(diisopropylamino]boryl]diazomethane with chloroborane. Photolysis of nitrilimines 6-9 afforded the corresponding carbodiimides 12-15. The regioselectivity and stereoselectivity of the 2 + 3 cycloaddition reactions of 6-8 with olefins were studied.