Stereocontrolled synthesis of the northern part of potent proteasome inhibitor TMC-95A

[GRAPHICS] A protected version of the northern part of TMC-95A, a potent and selective proteasome inhibitor, was synthesized with full stereochemical control. Highlights of this synthesis include (i) a (Z)-selective Mizoroki-Heck reaction to construct the oxyindole portion, (ii) a diastereoselective epoxidation, (iii) a 6-endo selective epoxide opening by Boc carbonyl group to establish the stereochemistry of C6, and (iv) a 1,3-elimination reaction of the L-allo-threonine derivative under Mitsunobu conditions to afford the (Z)-1-propenylamine.