From O-glucuronyl trichloroacetimidate (4) and ${Delta}^6$-tetrahydrocannabinol (5), the C-glucuronide of ${Delta}^6-tetrahydrocannabinol({Delta}^6-THC)$ (7) was obtained using mild Lewis acid catalysis. The known method for the synthesis of C-glucuronide from 1-O-unprotected glucuronide provided low chemical yields. The C-glucuronide of ${Delta}^6-THC$ was obtained through inversion of configuration at the anomeric center in O-glucuronyl trichloroacetimidate (4).