Cyclopropenes isocyanate

The reactive compound chlorosulfonyl isocyanate (ClSOaNCO, forms P-lactams even with unactivated alkenes, as well as with imines, allenes, conjugated dienes, and cyclopropenes. With microwave irradiation, alkyl isocyanates also... 

No addition occurs without irradiation, and attempts to obtain the azabicycle by addition of iodine isocyanate to the former cyclopropene led only to ring opened product, (287) 215). 

Another possibility for the preparation of bicyclic systems such as III/47 from three-membered rings can be realized by a [2+2] cycloaddition of the cyclopropene, III/41, and an unsaturated molecule, III/46, such as alkene, alkyne, ketene, ketenimine, ketone, isocyanate, etc. A large number of examples of this reaction type have been reviewed recently [55]x). 

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