Enantioselective Organocatalysis-Based Synthesis of 3-Hydroxy Fatty Acids and Fatty γ-Lactones

3-Hydroxy fatty acids have attracted the interest of researchers, since some of them may interact with free fatty acid receptors more effectively than their non-hydroxylated counterparts and their determination in plasma provides diagnostic information regarding mitochondrial deficiency. We present here the development of a convenient and general methodology for the asymmetric synthesis of 3-hydroxy fatty acids. The enantioselective organocatalytic synthesis of terminal epoxides, starting from long chain aldehydes, is the key-step of our methodology, followed by ring opening with vinylmagnesium bromide. Ozonolysis and subsequent oxidation leads to the target products. MacMillan’s third generation imidazolidinone organocatalyst has been employed for the epoxide formation, ensuring products in high enantiomeric purity. Furthermore, a route for the incorporation of deuterium on the carbon atom carrying the hydroxy group was developed allowing the synthesis of deuterated derivatives, which may be useful in biological studies and in mass spectrometry studies. In addition, the synthesis of fatty γ-lactones, corresponding to 4-hydroxy fatty acids, was also explored.

Robust and electron deficient oxidovanadium(iv) porphyrin catalysts for selective epoxidation and oxidative bromination reactions in aqueous media

Octamethoxy vanadylporphyrin (1) and its perbromo derivative (2) have been synthesized. 2 exhibited 100% selectivity for epoxide formation with very high TOF numbers. Remarkably, 2 biomimics vanadium bromoperoxidase (VBrPO) enzyme with extremely high TOF value in water.

A carbohydrate-derived trifunctional scaffold for medicinal chemistry library synthesis

For the generation of compound libraries for drug discovery a central scaffold containing three exit vectors with defined chirality was devised starting from commercially available tri-O-acetyl-glucal. Surprisingly, the reaction of a 4-O-mesylate with sodium azide did not lead to the expected 4-azido-4-deoxy derivative but to a 3-azido-3-deoxy regioisomer via intermediate epoxide formation. The absolute stereochemical configuration of the final tetrahydropyran building block was proven by X-ray crystallography. This scaffold endowed with a carboxylic acid, a secondary alcohol, and an azide functionality may be connected to a DNA tag at any of the three distinct exit vectors, thus providing ready access to several different compound libraries.Â

Epoxide formation from heterogeneous oxidation of benzo[a]pyrene with gas-phase ozone and indoor air

This work demonstrates the production of mono- and diol-epoxides from heterogeneous oxidation of benzo[a]pyrene with gas-phase ozone.

A versatile method of epoxide formation with the support of peroxy ionic liquids

A new method for the synthesis of epoxides in the presence of a peroxy ionic liquid as an oxidising agent and a solvent was developed.