Synthesis of Epigallocatechin Gallate Derivatives on Polymer Support

Significance

Solid-phase synthesis of epigallocatechin gallate derivatives was described. Thus, reaction of aldehyde 1 with polystyrene-Wang bromide gave the solid-supported aldehyde 2. The aldol condensation of the resulting aldehyde 2 with methylketone 3 under basic conditions afforded enone 4. After epoxidation of 4 with TBHP, the ring-opening reaction of the resulting epoxide with 1-dodecanethiol in the presence of Zn(OTf)₂ led to α-hydroxyketone 5. Reaction of 5 with 3,4,5-tribenzyloxybenzoic acid 6 in the presence of EDCI and DMAP gave ester 7. Treatment of 7 with TFA in the presence of the PS-benzaldehyde resin, followed by the addition of Et₃SiH provided the protected epigallocatechin 8. The Pd-mediated deprotection of 8 furnished epigallocatechin gallate 9.