Abstract:
6,6-DIALKYLTETRA-HYDRO- AND HEXAHYDRO-6H-DIBENZO (B,D) PYRANS (I) ARE OBTAINED BY CYCLODEHYDRATING A 1-(1''-HYDROXY)ALKYL-2-O-HYDROXYPHENYLCYCLOHEXANE OR -ONE (III). COMPOUNDS (III) ARE OBTAINED BY TREATING A 2-O-ALKOXY-PHENYLCYCLOHEXANE- OR ENECARBOXYLIC ACID OR ESTER (II) WITH A GRIGNARD REAGENT. ENANTIOMORPHIC COMPOUNDS (I), PARTICULARLY, (-) -$8-TETRAHYDROCANNABINOL, A BIOLOGICALLY ACTIVE, ASYMMETRIC CONSTITUENT OF HASHISH, ARE PREPARED BY CYCLIZING THE CORRESPONDING ENANTIOMORPHIC COMPOUNDS (III).