(-)-Epigallocatechin gallate (EGCG), a key component of green tea, as therapeutic effects with anticancer and antiallergic properties., exerted through its binding to the 67-kDa laminin receptor. The functionalization of EGCG...

In this study, we report a gold-catalyzed electrophilic aromatic substitution of protected (-)-epigallocatechin gallates (EGCG) with amidomethyl 2-alkynylbenzoates. Treatment of the amidomethyl 2-alkynylbenzoates with (Ph3P)AuOTf provided N-acyl imines under neutral conditions. The N-acyl imines underwent electrophilic aromatic substitution of EGCG at the electron-rich 8 and 6 positions of the A ring. This method facilitated direct modification of a protected EGCG to produce EGCG derivatives containing a (2,2-dimethyl-1,3-dioxan-5-yl)methyl sulfonyloxy group on the A ring, serving as synthetic precursors for 18F-labeled EGCGs. Importantly, the introduction of the radiohalogen labeling unit at the A ring of EGCG did not diminish their cytotoxicity against U266 cells compared to EGCG. Finally, we successfully synthesized a 18F-labeled EGCG via 18F-fluorination of the precursors followed by acidic deprotection.

The key step in the synthesis of the title compound (V) from the acetal (I) is the stannic chloride‐promoted ring‐closure of the β‐keto ester (IV) via intermediate formation of an allylic cation.

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