-Hydroboration-oxidation products in Δ-steroids a hydroboration--hydroboration mechanism.

Herein, we report for the first time a "-hydroboration-oxidation product" isolated and characterized under traditional hydroboration-oxidation conditions using cholesterol and diosgenin as substrates. These substrates are excellent starting materials because of the rigidity and different structural environments around the double bond. Further investigations based on experimental evidence, in conjunction with theoretical studies, indicate that the formation of this -species occurs a -hydroboration of the major product to generate the corresponding Δ-structure and the subsequent hydroboration by the β-face.

Practical access to axially chiral sulfonamides and biaryl amino phenols via organocatalytic atroposelective N-alkylation.

The importance of axial chirality in enantioselective synthesis has been widely recognized for decades. The practical access to certain structures such as biaryl amino phenols known as NOBINs in enantiopure form, however, still remains a challenge. In drug delivery, the incorporation of axially chiral molecules in systematic screening has also received a great deal of interest in recent years, which calls for innovation and practical synthesis of structurally different axially chiral entities.

Aza-Rubottom Oxidation: Synthetic Access to Primary α-Aminoketones.

An aza analogue of the Rubottom oxidation is reported. This facile transformation takes place at ambient temperature and directly converts silyl enol ethers to the corresponding primary α-aminoketones. The use of hexafluoroisopropanol (HFIP) as the solvent is essential for the success of this reaction.

Direct Primary Amination of Alkylmetals with NH-Oxaziridine.

A method for the primary electrophilic amination of primary, secondary, and tertiary organometallic substrates from a bench-stable NH-oxaziridine reagent is described. This facile and highly chemoselective transformation occurs at ambient temperature and without transition metal catalysts or purification by column chromatography to provide alkylamine products in a single step. Density functional theory (DFT) calculations revealed that, despite the basicity of alkylmetals, the direct NH-transfer pathway is favored over proton and O-transfer.

Copper-Catalyzed Synthesis of Hindered Ethers from α-Bromo Carbonyl Compounds.

A catalytic method for the synthesis of sterically hindered ethers and thioethers from α-bromo carbonyl compounds and the corresponding nucleophiles using an inexpensive Cu(I) catalytic system is reported. This facile transformation takes place at ambient temperature and does not require the exclusion of air or moisture; thus, it is well-suited for the functionalization and derivatization of complex organic molecules.