To obtain a substituted chroman derivative in a high yield by reaction of a substituted acrolein with acrylonitrile or the like to form the corresponding dihydropyran which is then reacted with an acid to form the corresponding oxotetrahydropyran which is reacted with a substituted vinyl ketone to form the corresponding chromenone derivative which is then dehydrogenated.

This substituted chroman derivative, a compound of formula V, is obtained by reaction of a substituted acrolein of formula I (R1 is a 1-4C alkyl, 6-18C aryl, or the like) with a compound of formula II (R2 is a 1-23C alkyl, 2-23C alkenyl, or the like) (e.g. methyl methacrylate, 2-methyl-3- methoxypropane) to form the corresponding 3,4-dihydro-2H-pyran of formula III which is then reacted with an acid to form the corresponding 5- oxotetrahydropyran which, in turn, is reacted with a substituted vinyl ketone to form the corresponding chromen-6-one derivative of formula lV(R4 to R6 are each H or a 1-4C alkyl) which is then dehydrogenated.