Patent ID: 7781427

Claim:
A method comprising the steps of: a) providing a compound of formula I: wherein: R 1 is alkyl, alkanoyl, aroyl, carboalkoxy, or carboalkoxyaryl; R 2 and R 3 are, independently, hydrogen, hydroxy, alkyl, alkoxy, halogen, carboxamido, carboalkoxy, perfluoroalkyl, cyano, alkanesulfonamido, alkanesulfonyl, alkanamido, amino, alkylamino, dialkylamino, perfluoroalkoxy, alkanoyloxy, alkanoyl, aroyl, aryl, arylalkyl, heteroaryl, or heteroarylalkyl; R 6 and R 7 are, independently, hydrogen or alkyl; n is 1; and b) contacting the compound of formula I with at least one formaldehyde equivalent and a reagent having either formula R 4 —CH═CH—R 5 or formula R 4 —C≡C—R 5 , in the presence of a Lewis acid and a reaction solvent to form a compound of formula II: wherein the formaldehyde equivalent is in solid form at least prior to the contacting, R 1 is alkyl, alkanoyl, aroyl, carboalkoxy, or carboalkoxyaryl; R 2 and R 3 are, independently, hydrogen, hydroxy, alkyl, alkoxy, halogen, carboxamido, carboalkoxy, perfluoroalkyl, cyano, alkanesulfonamido, alkanesulfonyl, alkanamido, amino, alkylamino, dialkylamino, perfluoroalkoxy, alkanoyloxy, alkanoyl, aroyl, aryl, arylalkyl, heteroaryl, or heteroarylalkyl; R 6 and R 7 are, independently, hydrogen or alkyl; n is 1; R 4 and R 5 are taken together with the carbons to which they are attached, form a cyclic moiety that is cycloalkyl, cycloalkenyl, bridged bicyclic alkyl, bridged bicyclic alkenyl, pyranyl or thiopyranyl in which the sulfur atom is optionally oxidized to the sulfoxide or sulfone; and the dotted line represents an optional double bond.