Synthesis of 3-Allylchromones, Homoisoflavones and Bischromones from ( E )-1-(2-hydroxyphenyl)-3-( N,N -Dimethylamino)prop-2-en-1-One

( E)-1-(2-Hydroxyphenyl)-3-( N,N-dimethylamino)prop-2-en-1-one reacts with allyl bromide, prenyl bromide, benzyl bromide and α,α’-dibromo- p-xylene in DMF to produce 3-allyl-, 3-prenyl-chromones, homoisoflavones and bischromones, respectively. Similar compounds were also obtained by deformylative allylation or benzylation of 3-formylchromone.