Michael-Henry acetalization-oxidation

Oxabicyclo[3.3.1]nonan-2-ones (113) containing four consecutive stereogenic centres have been prepared in >99% ee by a cascade organocatalytic Michael-Henry acetalization-oxidation reaction of glutaraldehyde (114) and 3-aryl-2-nitroprop-2-enols (115). The structures and absolute configurations of the products were confirmed by X-ray crystallography. 

Aliphatic nitro compounds are versatile building blocks and intermediates in organic synthesis,14 15 cf. the overview given in the Organic Syntheses preparation of nitroacetaldehyde diethyl acetal.16 For example, Henry and Michael additions, respectively, lead to 1,2- and 1,4-difunctionalized derivatives.14 18 1,3-Difunctional compounds, such as amino alcohols or aldols are accessible from primary nitroalkanes by dehydration/1,3-dipolar nitrile oxide cycloaddition with olefins (Mukaiyama reaction),19 followed by ring cleavage of intermediate isoxazolines by reduction or reduction/hydrolysis.20 21... 

---