Access to valuable building blocks by the regio- and enantioselective ring opening of itaconic anhydride by lipase catalysis.

Herein, we report for the first time the highly regio- and enantioselective ring opening of a biobased itaconic anhydride catalyzed by the Pseudomonas cepacia lipase (PCL) in tert-butyl methyl ether (TBME) at room temperature. This method is easy, efficient and eco-friendly and can be performed in one step with a series of highly valuable monoester itaconates (achiral or enantioenriched) using various alcohols as nucleophiles with 100% atom economy. In all cases, the ß-monoester isomer was the predominant product of the reaction. Using achiral primary alcohols as substrates, a variety of novel itaconates were obtained in moderate to excellent yields (50-90%). For select examples, product characterization was carried out using X-ray diffraction, in addition to the standard techniques. The application of this approach was performed for the preparation of enantioenriched 4-monoester itaconates via enzymatic kinetic resolution.

Efficient access to both enantiomers of 3-(1-hydroxyethyl)phenol by regioselective and enantioselective CAL-B-catalyzed hydrolysis of diacetate in organic media by sodium carbonate.

In the present paper, we describe several pathways employing immobilized lipase from Candida antarctica B (CAL-B) as biocatalyst to prepare easily both enantiomers of 3-(1-hydroxyethyl)phenol. We have applied hydrolysis with Na2 CO3 in organic media under mild conditions. The reaction parameters solvent effect, amount of lipase, and Na2 CO3 were examined with 3-(1-acetoxyethyl)phenyl acetate as substrate. In alkaline hydrolysis, (R)-3-(1-hydroxyethyl)phenol was obtained with ee = 99% and (S)-(-)-3-(1-acetoxyethyl)phenol with ee = 98% at optimal conversion (c = 50%) and high selectivity (E > 200). Two other deacylation reactions were compared: alcoholysis with MeOH and with NEt3 . The acylation of 3-(1-hydroxyethyl)phenol with vinyl acetate was also examined. Alkaline hydrolysis gave the best results, while good regioselectivity and enantioselectivity were observed in alcoholysis and acylation reactions. Finally, (S)- and (R)-3-(1-hydroxyethyl)phenol (ee > 98%), key intermediates for the synthesis of important drugs, were prepared from the corresponding racemic diacetate through alkaline hydrolysis.