An easy and efficient synthesis of 3-nitrochromans

The reaction of nitro olefins reacted with (E)-(2-hydroxyphenyl)-1-nitroethylene in the presence of DABCO generates 3-nitrochroman with a high stereoselectivity. A possible reaction mechanism for the reaction and the transition states involved in producing the final product are proposed. The treatment of 3-nitrochromans with t-BuOK give alkenes.