The present invention relates to processes and intermediates for the preparation of compounds of formula (I): or a salt or oxide thereof wherein Alk, M1, M2, R1, R2, R3, R4, R5, R6, R7, and n are as described herein. The present invention also relates to compounds of formula (I) and composition comprising a compound of formula (I). Also disclosed is a method of altering or improving the taste of a composition that includes adding to the composition at least one compound of formula (I), in an amount effective to obtain a modified composition having altered or improved taste relative to an otherwise identical composition lacking said compound.