Chiral Reagents (r) -4 - Methyl-gamma-butyrolactone Preparation And Spices Synthesis Of Citralis Nitrile

Steroidal sapogenins are valuable starting materials in the industry of steroid chemistry. During the development of the Green and Resource Chemistry,our group has invented an efficient and environmemt-friendly method to degrade steroidal sapogenins with hydrogen peroxide,and the optically pure(R)-5-methyl-tetrahydropyran-2-one and(R)-4-methyl-dihydrofuran-2(3H)-one can be obtained from the reaction of steroidal sapongenins' degradation.My master dissertation work mainly focused on obtaining the(R)-4-methyl-dihydrofuran-2(3H)-one from the Tigogenin's oxidative drgradation in 50%yield by reseaching on the drgradation's costoff,then converted it into(R)-4-bromo-3-metbylbutanoic acid ethyl ester with HBr/EtOH in 86%yield;(S)-ethyl-4-cyano-3-methylbutanoate was obtained by the reaction of(R)-4-bromo-3-methylbutanoic acid ethyl ester with sodium cyanide in 87%yield;Via modulating the quantity of benzyl bromide and changing the final treatment,(R)-4-benzyioxy-3-methylbutanoicacid and(R)-4-benzyioxy-3-methylbutanoic acid benzyl ester were preparated by the reaction of benzyl bromide with the hydrolyzed(R)-4-methyl-dihydrofuran-2(3H)-one in 91%,90%yield respectively.These chiral reagents not only provide the important synthetic intermediates for the chiral drugs and the optically active natural compounds,they also make the opportunities for their new synthetic routes design.For example,we used these chairal reagents for the synthesis of(R)-Citralis Nitrile.We gained the intermediate product(R)-4-(benzyloxy)-3-methyl-1-phenylbutan-1-one by the reaction of(R)-4-benzyloxy-3-methylbutanoic acid with phenyl lithium,then deoxidized its carbonyl, deprived its benzyl,bromized the hydroxyl,converted the hydroxyl into cyan with the sodium cyanide and synthesized the(R)-Citralis Nitrile for 5 steps in 52%yield.