Hydrogen Bond Controlled anti-Aza-Michael Addition: Diastereoselective Synthesis of Cyclobutene-Containing Amino Acid Derivatives.

This research was supported by the Spanish Ministerio de Economia y Competitividad (MINECO), the European FEDER and Regional Development Fund (grant numbers CTQ2011-28417-C01-02, CTQ-2013-44303-P), and the Red de Excelencia Consolider (grant number CTQ2014-51912-REDC). G. M.-A. thanks the Spanish Ministerio de Educacion y Ciencia (MEC) for an FPU grant. The ORFEO-CINQA network is also acknowledged.