A Novel and Selective Desilylating Method for Trialkylsiltl Ethers and Enzymatic Resolution of (E)-r-Tributylstannyl Allylic Alcohol and It''s Application in Drug Synthesis

• Main Authors: Yeh, Hsiu-Chih, 葉修志
• Other Authors: Adam Shih-Yuan Lee
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/76415214719107093822

博士 === 淡江大學 === 化學學系 === 86 === Part I: Trimethylsilyl ethers (0.25M) are deprotected to theirs correspondingalcohols in CCl4/CH3OH (v/v=1:1) under sonication for 15 minutes in a commercialultrasonic cleaning bath (39kHz). The selective deprotection of tert-butyldimethyl- silyl ethers of primary alcohols is achieved under ultrasonic condition (Scheme I). A series of tert-butyldimethylsilyl, triisopropylsilyl, tert-butyldi-phenylsilyl ethers are converted to theirs corresponding alcohols in CBr4/CH3OH (0.1eq/10 mL) reaction system under refluxing condition(Scheme II). The chemoselectivity can be achieved between primary andsecondarytriisopropylsilyl ether when more hindered 2-propanol is used instead of methanol.Part II: Lipase AK (from Pseudomonase sp.) catalyzed the enantio- selectivetransesterification of racemic (E)-g-tributylstannyl allylic alcohols 37 with vinyl acetate in hexane (SchemeIII). The enantiomericexcess of the allylic alcohols were determined by 19F-NMR analysis of theirs correspondingMosher*s esters.The optically active alcohol (S)-37a was protected to triethylsilylether and it was further applied in total synthesis of PGE1 methyl ester (Scheme IV).