CHEMISTRY OF CYCLIC AMINOOXYCARBENES

A series of oxazolidin-2-ylidenes and one tetrahydro-1,3-oxazin-2-ylid ene, generated by thermolysis of Delta(3)-1,3,4-oxadiazolines in benze ne at 90 degrees C, were intercepted by insertion into the OH bond of phenols. In two cases the initial products rearranged to N-(2-aryloxye thyl)-N-methylformamides. The activation energy for rotation about the amide CN bond of those ultimate products was measured as 20.4 kcal/mo l. The aminooxycarbenes reacted with two equivalents of methyl or phen yl isocyanate to give spiro-fused hydantoins. Major products from the reactions of the N-carbonyl carbenes with dimethyl acetylenedicarboxyl ate or with methyl propiolate were 2-oxazolines resulting from apparen t acyl transfers from N to C in the proposed dipolar intermediates; mi nor products of 1:2 (carbene:trap) stoichiometry were also observed.