The Development of a Sulfamate-Tethered Aza-Michael Cyclization Allows for the Preparation of (−)-Negamycin tert-Butyl Ester

We present the first examples of intramolecular aza-Michael cyclizations of sulfamates and sulfamides onto pendant α,β-unsaturated esters, thioesters, amides, and nitriles. Stirring the substrate with catalytic quantities of the appropriate base delivers the product in good yield and excellent diastereoselectivity. The reactions are operationally simple, can be performed open to air, and are tolerant of a variety of important functional groups. We highlight the utility of this technology by using it in the preparation of a (−)-negamycin derivative.