REACTIONS OF ACYL ISOCYANATES

The reaction of norbornadiene with trichloroacetyl isocyanate is shown to proceed via a novel cyclization to give tetrahydro-2-trichloromethyl-5,8-methano-4H-1,3-benzoxan-4-one. The structure of this product and the mechanism of its formation is discussed. Similar reactions occurred with norbornene and dicyclopentadiene. Enamines and vinyl ethers reacted with acyl isocyanates to give adducts in which the isocyanate had, in effect, replaced the β proton of the enamine or vinyl ether. Adducts of acyl isocyanates with indole and pyrrole are reported. Reactions of N,N-disubstituted formamides with trichloroacetyl isocyanate proceeded with the loss of carbon dioxide and formation of acyl formamidines. Conventional reactions of acyl isocyanates with nucleophiles are reported. © 1969, American Chemical Society. All rights reserved.