Total Synthesis of Chrysosporazines B and C

The first total synthesis of chrysosporazines B and C was accomplished in a concise and highly stereoselective manner with overall yields of 9.2% and 8.0%, respectively. Highlights of the synthesis include a Suzuki-Miyaura coupling of E-enol tosylate followed by Rh-catalyzed asymmetric hydrogenation to establish the nonsymmetric β,β-diaryl amino acid motif, a piperazinedione condensation and reduction to construct the piperazine framework, and a late-stage Pd-catalyzed carbonylation to furnish the hexahydro-6H-pyrazino[1,2-b]isoquinolin-6-one scaffold.