Aminohydroxylation followed by Cyclodehydration

As can be seen from the examples in Tables 12.6-12.8, excellent yields of the hydroxysulfonamide products were obtained from each of the olefins examined. It is noteworthy that these high yields were achieved at high substrate concentrations and room temperature in the presence of as little as 0.10 mol% catalyst. 

The strategy involved the activation of the hydroxy group as the mesylate in the first step and subsequent ring-closure with DBU as the base. Small-scale reactions 

8 equiv NEt3, CH2CI2, 0°C, 1 h, then reflux 5-6 h then, 0.3-0.5 equiv MsCI, 

Entry Substrate Scale (mmol) Catalyst (mol%) Combined yield (regioselectivity)[a  

The generality of this method for large-scale preparations was demonstrated for the syntheses of toluenesulfonyl aziridines from aminohydroxylation products of N-substituted cinnamamides (Table 12.9). The results of synthesis of other sulfo-nyl aziridines are summarized in Tables 12.10 and 12.11. 

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