Study On Highly Efficient Green Synthesis Of ?-Butyrolactone By Allyl Boron Reagent And Aldehyde

The stucture of ?-butyrolactone is a key skeleton in numerous natural products and pharmaceuticals.The ?-butyrolactone and its derivatives are widely present in natural products and drugs as well as some organic functional materials.Currently,because of its widely applicatons,the research on the synthesis method of the ?-butyrolactone has become a hot topic for chemist.The allyl boron reagents have the advantages of low toxicity and stability.Moreover,the diastereoselective addition of carbonyl compounds with ?-branched allyl to synthesize the cyclic lactone is not only green,but also simple and efficient.The stereoselective allylation of a carbonyl compound with an allyl boron reagent followed by lactonization is a very efficient synthetic strategy for the synthesis of lactones.In this research,a series of aldehydes were used as starting materials,which were reacted with chiral allyl boron reagent followed by lactonization to afford a series of single isomeric forms of lactone.In order to find the optimal reaction conditions,the four main reaction conditions were investigated such as solvent,catalyst,reaction time and temperature.Surprisingly,the reaction can achieve good to excellent yield from 68% to 92% under water as the only solvent.The study was also found that both the aliphatic and aromatic aldehydes can synthesize a single isomer of the?-butyrolactone,which proves that the synthesis method is not only green,efficient but also universal.Additionally,the configuration of cycliclactone was also discussed and studied.The formal synthesis of natural paraconic acids was successfully carried out by this method,which also proved that the method is practical.