We next examined the effect of varying the substituent on the aziridine nitrogen (Scheme 4). In general, to successfully engage, the aziridine had to be "activated" with an electron-withdrawing group. A variety of such moieties were well tolerated, including methanesulfonyl, 2-thiophenesulfonyl, 4-bromophenylsulfonyl, 4-nitrobenzenesulfonyl, 2,5-difluorobenzenesulfonyl, and 2-naphthalenesulfonyl groups (Scheme 4, Entries 1-6). Tosyl groups can be difficult to remove from amines, often requiring harsh reagents like lithium aluminum hydride or dissolving metal conditions with poor functional group compatibility. In contrast, nitrobenzenesulfonyl (nosyl) groups are much more amenable to removal, often with room temperature treatment with thiolate nucleophiles; thus, we were pleased that nosylated aziridines were fully compatible with our optimized protocol. There was no productive reaction with Nphthalimido-aziridine substrate 24; only decomposition of starting material was observed (Scheme 4, Entry 7). We hypothesize that the known instability of phthalimide protecting groups in a basic milieu underlies this. With all substrates tested (Scheme 5), the cyclization was perfectly regioselective and stereospecific. In all cases, the pendant sulfamate auxiliary the aziridine with 6-exoselectivity give 6-membered oxathiazinane heterocycles bearing vicinal diamines. Trans-aziridine sulfamate starting materials gave products with an erythro-configuration; conversely, cis-aziridine sulfamates gave products with a threoconfiguration. With our optimized protocol, cis, trans, and terminal aziridine sulfamates were competent cyclization substrates but, in some instances, with differing reactivity. For example, cis-aziridine N-cyclohexyl sulfamate 11 (Scheme 3) gave no reaction, even with extended reaction times; in sharp contrast, trans-aziridine N-cyclohexyl sulfamate 27 cyclized efficiently (Scheme 5, Entry 1). Crystal structures of products 26 (CCDC: 2277022) and 28 (CCDC: 2277021) allowed for unambiguous determination of relative stereochemistry. The identities of other products were assigned by analogy. Multi-fold increases in scale were tolerated without erosion of yield or selectivity (Scheme 6).