The recent advancement of highly selective catalytic methods for the amination of CÀH bonds has inspired novel approaches to complex natural products. [1] Our efforts to expand this chemistry further have led to the identification of a distinct class of 1,2,3-oxathiazinane-2,2-dioxide heterocycles 2, made accessible through sulfamate ester 1 insertion into ethereal C a À H centers (Scheme 1). [2,3] Herein, we demonstrate a simple and effective method, which capitalizes on catalyst-controlled regioselective CÀH oxidation, for assembling these unique N,O-acetals 2. Such compounds display exceptional versatility as iminium ion equivalents, coupling smoothly and with high diasteroinduction to allyl silanes, enol ethers, silyl ketene acetals, and, as reported previously, alkynyl zinc reagents. [2] From these studies has evolved a broadly predictive stereochemical model for nucleophilic addition reactions with 2. In all, the stereoselective assembly of functionalized oxathiazinanes through this efficient twostep sequence opens untapped possibilities for CÀH amination in synthesis. [4] Metal-carbene and metal-nitrene oxidants display a high proclivity for insertion into ethereal C a ÀH bonds. [5] In principle, this bias can be exploited to direct site selectivity in amination reactions of substrates that possess multiple reactive CÀH centers. Such conjecture is readily tested with sulfamates 4-7 (Scheme 2). Each of these compounds can Scheme 1. Oxathiazinane N,O-acetals as iminium ion equivalents.