Patent ID: 7820835

Claim:
A method for producing flavan derivatives comprising the steps of: (1) dehydratively condensing a phenol compound expressed by formula (I) and an alcohol compound expressed by formula (II) to obtain an epoxide compound of formula (III), (wherein R represents, in each of the appearances, H; an allyl group; or an alkyl group, an aryl group or an arylalkyl group, which may be substituted by an alkoxy group, an alkylthio group, an acyloxy group, or an alkoxycarbonyl group; n represents an integer from 0 to 4; and m represents an integer from 0 to 5); (2) opening the epoxy ring of the epoxide compound of formula (III) to obtain an iodine-containing compound of formula (IV), (wherein R represents, in each of the appearances, H; an allyl group; or any one of an alkyl group, an aryl group or an arylalkyl group which may be substituted by an alkoxy group, an alkylthio group, an acyloxy group, or an alkoxycarbonyl group; n represents an integer from 0 to 4; m represents an integer from 0 to 5; X represents a halogen, an alkylsulfonyloxy group, or an arylsulfonyloxy group; and Q represents H; a silyl group; or an alkyl group, an aryl group or an arylalkyl group which may be substituted by an alkoxy group, an alkylthio group, an acyloxy group or an alkoxycarbonyl group); (3) cyclizing the iodine-containing compound of formula (IV) to obtain a flavan derivative of formula (V), (wherein R represents, in each of the appearances, H; an allyl group; or an alkyl group, an aryl group or an arylalkyl group which may be substituted by an alkoxy group, an alkylthio group, an acyloxy group or an alkoxycarbonyl group; n represents an integer from 0 to 4; m represents an integer from 0 to 5; and Q represents H; a silyl group, or an alkyl group, an aryl group or an arylalkyl group which may be substituted by an alkoxy group, an alkylthio group, an acyloxy group, or an alkoxycarbonyl group).