DPP4 and type 2 diabetes mellitus: ABT-341 is a highly potent, selective, and orally bioavailable DPP4 (dipeptidyl peptidase IV) inhibitor, which is a drug candidate for type 2 diabetes being developed by Abbott Laboratories.35 We accomplished a one-pot sequential synthesis of ATB-341 based on an organocatalyst-mediated Michael reaction as a key step (Scheme 4).