A-heteroatom-substituted amides

Alternatively, the electron-withdrawing properties of the a-heteroatom and its ability to coordinate Sml2 may facilitate reduction of the ester carbonyl group and formation of ketyl radicals 37 (Scheme 4.22). Once the activating heteroatom group has been removed, no further ester reduction is possible. A similar mechanism is possible for the reduction of a-heteroatom-substituted amides. 

Reduction of a-Heteroatom-substituted Amides with Sml2... 

Fewer examples of the reduction of a-heteroatom-substituted amides with Sml2 have been reported. Molander studied the reduction of tV-tosylaziridine-2-carboxamides with Sml2. As in the reduction of aziridine-2-carboxylates, the addition of DMAE was required for the reaction to proceed with high regio-chemical control (Scheme 4.32).32 It was also possible to reduce A-methoxy-tV-methylaziridine-2-carboxamides with Sml2 provided that the temperature and the amount of Sml2 were carefully monitored to prevent N-O bond reduction (see Section 4.6.2).32... 

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