From Unsaturated Iminophosphoranes and

The reaction of unsaturated iminophosphoranes 5 with arylisocyanates affords mono unsaturated carbodiimides 6. The compounds are stable at room temperature in acetonitrile solution, but they cannot be distilled under vacuum. 

As byproducts divinylcarbodiimides are formed. A better way to synthesize divinylcarbo-diimides is the reaction of 5 with 6P In this manner N,N -bis[l-(4-methylphenyl)-2-phenylvinyljcarbodiimide, mp 135 °C, is obtained in 38 % yield. 

reaction of (5,5-dimethyl-3-oxo-l-cyclo-hexenyl)iminotriphenylphosphorane 7 with isocyanates affords N-(5,5-dimethyl-3-oxo-l-cyclohexenyl)-N -phenylcarbodimide 8.1  

5-cycloheptatrienyl)-N -phenylcarbodiimide is obtained in 82 % yield from the corresponding iminophosphorane and phenyl isocyanate.  

Likewise, reaction of the seven membered ring heterocyclic iminophosphoranes 9 with phenyl isocyanate gives the corresponding carbodiimides 10.  

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