One‐Pot High‐Yielding Synthesis of the DPP4‐Selective Inhibitor ABT‐341 by a Four‐Component Coupling Mediated by a Diphenylprolinol Silyl Ether

A dream come true: ABT-341 was synthesized in high yield with excellent diastereo- and enantioselectivity in a one-pot process mediated by a diphenylprolinol silyl ether (see scheme; TMS=trimethylsilyl). Thus, an asymmetric Michael reaction, a domino Michael/Horner–Wadsworth–Emmons reaction combined with a retro-aldol reaction, base-catalyzed isomerization, amide-bond formation, and reduction of the nitro group all took place in a single flask.