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Arylacetonitriles are able to participate in organocatalytic Michael additions to α,β-unsaturated aldehydes by incorporating a nitro group at the phenyl ring, which acts as a temporary activating group in a remote position and allows further transformations. The sequential protocol Michael addition/NaBH4reduction/lactonization allows the synthesis of diastereomerically pure disubstituted lactones in high yield and optical purity. [ABSTRACT FROM AUTHOR]

B 2 nep 2 efficiently promotes the N-O cleavage of nitrones to form imines in very high yields via a simple, efficient, sustainable, functional group tolerant and scalable protocol. The reaction occurs in the absence of additives through a concerted mechanism. We demonstrated that DMPO and TEMPO, typically used as radical traps, are also deoxygenated by diboron reagents, which demonstrates their limitation as mechanistic probes.

Optically pure cyano tert-alkyl sulfones have been obtained by organocatalytic enantioselective Michael addition of alpha-substituted cyanosulfones to vinyl ketones using cinchona alkaloids as catalysts. The best results were obtained for p-trifluorophenylsulfones by using VIII as catalyst in toluene at -40 degrees C. Reactions proved to be applicable for a variety of alpha,beta-unsaturated ketones, affording alpha,alpha-disubstituted cyanosulfones in excellent yields with er's up to 90:10.

[Reaction: see text] A simple procedure to obtain N-sulfonyl imines involving the condensation of carbonyl compounds with p-tolyl or tert-butyl sulfinamides followed by oxidation with m-CPBA of the resulting N-sulfinylimines is reported. The method is applicable to aldehydes (aliphatics and aromatics) and ketones (diaryl, dialkyl, and aryl alkyl), even those containing enolizable protons. It also does not affect C=N or C=C double bonds and does not epimerize alpha-stereogenic centers.