Chemoselective deacylation of functionalized thioesters catalyzed by Dy(OTf)34-Acetoxybenzyl carbonate: Lanthanide(III) metal-catalyzed removable orthogonal protecting group of carbohydrates

• Main Authors: Jiun-Rung Guo, 郭峻榕
• Other Authors: Chien-Fu Liang
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/35522397772839551856

碩士 === 國立中興大學 === 化學系所 === 105 === In the first part of this thesis, we reported an efficient and convenient synthetic approach to thioacetate deprotection by utilizing Dy(OTf)3 catalyst under mild heating conditions. Compared with traditional method, our reaction conditions are milder catalytic systems, and reduced byproduct such as disulfide bond formation. We also investigated the feasibility of chemoselecctive S-deacetylation of functionalized thioester molecules and resulted in good yields. Furthermore, the Dy(OTf)3 is an environmentally friendly catalyst, and we have conducted a recyclable used strategy for S-deacetylation. The second part of this thesis, we have developed the 4-acetoxybenzyl(4-nitrophenyl)carbonate (ABNPC) as a new orthogonal protecting group for carbohydrate. The ABNPC group is readily prepared starting from the commercially available, inexpensive 4-hydroxybenzyl alcohol. The ABNPC group can be selective removed using ytterbium(III) trifluoromethanesulfonate without affecting a series of common protecting groups. According to experimental results, this reaction is mild condition without other additives, and orthogonal with commonly used benzoyl, benzyl, p-methoxybenzyl and benzylidene groups.