Choline hydroxide as an efficient catalyst for the diastereoselective synthesis of trans-2,3-dihydrofuro[3,2-c]coumarins in an aqueous medium

A one-pot, three-component condensation of 2-[2-(4-chlorophenyl)-2-oxoethyl] isoquinolinium bromide with 4-hydroxycoumarin and an aromatic aldehyde in the presence of catalytic amounts of choline hydroxide in refluxing water gave trans-2-(4-chlorobenzoyl)-3-(aryl)2,3-dihydro-4H-furo[3,2-c]chromen-4-ones in excellent yields and with short reaction times.