| Abstract
| - N,N-Dichloro-o-nitrobenzenesulfonamide (2-NsNCl2) was found to be an effective electrophilicnitrogen source for the direct diamination of α,β-unsaturated ketones without the use of any metalcatalysts. The reaction is very convenient to carry out without the protection of inert gases. Molecularsieves (4 Å) and temperature were found to play key roles in controlling the formations of3-trichloromethyl and dichloromethyl imidazoline products (16 examples). The 2-Ns-protection groupof the resulting diamine products can be easily cleaved under mild Fukuyama's conditions. A newmechanism hypothesis of [2+3] cyclization and N-chlorination has been proposed to explain theproduct structures, particularly their regio- and stereochemistry.
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