Alpha-carboxy-6-nitroveratryl: a photolabile protecting group for carboxylic acids.

The synthesis of a new photolabile protecting group for carboxylic acids, alpha-carboxy-6-nitroveratryl (alphaCNV), is described. Bromide 3, prepared in four steps from 3,4-dimethoxyphenylacetic acid, was used to alkylate carboxylic acids under mild conditions in good yield. Palladium-catalyzed deallylation afforded the acids 4a-h, which underwent rapid and quantitative photolysis at wavelengths longer than 300 nm to liberate the carboxylic acid in good to quantitative yield.

A Brønsted acid mediated cascade enone synthesis from aldehydes containing a tethered propargylsilane.

MeSO3H effects the intramolecular allenylation of a series of aldehydes 1 to provide allenyl alcohol product 3 as a single diastereoisomer. Cyclization proceeds rapidly at -78 degrees C. However, when the reaction is performed at room temperature, aldehyde 1 provides enone product 7 instead.

Sugar bislactones by one-step oxidative dimerisation with pyridinium chlorochromate versus regioselective oxidation of vicinal diols.

Synthesis of 10-membered bislactones by PCC oxidation of methyl 2,6-di-O-pivaloyl-alpha-D-glucopyranoside and methyl 4,6-O-benzylidene-alpha-D-glucopyranoside is described, with emphasis on their structure elucidation using the information gained by combination of NMR spectroscopic techniques with X-ray diffraction data. In alternative, the use of PCC and PCC adsorbed on silica gel or alumina for the regioselective oxidation of vicinal diols in sugars is also reported. Both bislactones showed antifungal activity against Candida albicans, and were slightly active against the bacteria Bacillus subtilis.