SmI2-mediated cross-coupling of nitrones with β-silyl acrylates: synthesis of (+)-australine.

The SmI(2)-mediated cross-coupling of nitrones with β-silyl-α,β-unsaturated esters, followed by zinc reduction, allows an efficient and highly diastereoselective preparation of β-silyl lactams, which are precursors of β-hydroxy lactams through Tamao-Fleming oxidation. By applying the method to a cyclic, carbohydrate-derived nitrone, a new synthesis of (+)-australine has been realized in only 11 steps and in 21% overall yield from L-xylose.