Diester compound having a dimethylcyclobutane ring, a process for preparing the same, and a process for preparing dimethylcyclobutane compound derived from the diester compound

A process for preparing an isopropenyl dimethylcyclobutane compound of formula (6):

• wherein X3 is selected from the group consisting of a hydroxyl group, an acyloxy group having 1 to 10 carbon atoms including a carbon atom of a carbonyl group, an alkoxycarbonyloxy group having 2 to 10 carbon atoms including a carbon atom of a carbonyl group, an alkanesulfonyloxy group having 1 to 10 carbon atoms, an arenesulfonyloxy group having 6 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, a silyloxy group having 3 to 20 carbon atoms, and a halogen atom,
• the process comprising:
• subjecting a diester compound of formula (1), having a dimethylcyclobutane ring:
• wherein R1 and R2 represent, independently of each other, a monovalent hydrocarbon group having 1 to 10 carbon atoms,
• to a reduction reaction to produce a diol compound of formula (4), having a dimethylcyclobutane ring:
• changing a hydroxyl group in the moiety of HOCH2—(CH3)C═ in the diol compound of formula (4) and optionally a hydroxyl group in the moiety of —CH2OH in the diol compound of formula (4) to X1 and X2, respectively, to prepare a dimethylcyclobutane compound of formula (5):
• wherein X1 is selected from the group consisting of an acyloxy group having 1 to 10 carbon atoms including a carbon atom of a carbonyl group, an alkoxycarbonyloxy group having 2 to 10 carbon atoms including a carbon atom of a carbonyl group, an alkanesulfonyloxy group having 1 to 10 carbon atoms, an arenesulfonyloxy group having 6 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, a silyloxy group having 3 to 20 carbon atoms, a trialkylphosphonio group having 3 to 30 carbon atoms, a triarylphosphonio group having 12 to 30 carbon atoms, and a halogen atom;
• and X2 is selected from the group consisting of a hydroxyl group, an acyloxy group having 1 to 10 carbon atoms including a carbon atom of a carbonyl group, an alkoxycarbonyloxy group having 2 to 10 carbon atoms including a carbon atom of a carbonyl group, an alkanesulfonyloxy group having 1 to 10 carbon atoms, an arenesulfonyloxy group having 6 to 20 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, a silyloxy group having 3 to 20 carbon atoms, and a halogen atom;
• and
• subjecting the dimethylcyclobutane compound of formula (5) to a reduction reaction to produce the isopropenyl dimethylcyclobutane compound of formula (6).