Enals Henry reaction

Stereoselective synthesis of highly functionalized azatricycles (e.g., 75) has been achieved by copper-catalysed Henry reaction of enals with nitromethane, zinc reduction of the nitro group and subsequent tosylation, followed by iodocyclization. The iodine is easily removed afterwards by hydrogenation, or can be used to introduce other functionality, such as by epoxidation of the adjacent alcohol. 

Oxo-hept-5-enals undergo an organocatalytic one-pot reaction with nitromethane to give trisubstituted cyclohexanols with three contiguous chiral centres de of >98% is reported and ee up to 96%. The process is a tandem Henry-Michael, followed by a 0 tandem retro-Henry-Henry. Consistent with this sequence is the finding that the use of 0 the racemic Henry product as substrate gives similar final results. 

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