N-15 nuclear polarization in the reactions of diallyl ether with nitrogen dioxide

The reaction of diallyl ether with nitrogen dioxide in organic solvents yie lds a mixture of cis and trans 2,3-bis(nitromethyl)-tetrahydrofurans, cis a nd trans 2-nitratomethyl-3-nitromethyl-tetrahydrofurans and a number of str aight-chain compounds with one to four nitro groups. Under the conditions u sed, the cyclic compounds form the main products when the solution of nitro gen dioxide is slowly added to the solution of diallyl ether but not when t he reverse mode of addition is used. When N-15-nitrogen dioxide is used, th e products show strong N-15 nuclear polarization: the 2,3-di(nitromethyl)-t etrahydofurans give an emission signal, and one straight-chain product with two nonequivalent nitro groups shows both an emission signal and an enhanc ed absorption signal. For both the cyclic and straight-chain products, the nuclear polarization is consistent with the successive reactions of diallyl ether with two nitrogen dioxide radicals with uncorrelated spins.