陳建添Chien-Tien Chen楊文傑wen-chieh Yang2019-09-04不公開2019-09-042009http://etds.lib.ntnu.edu.tw/cgi-bin/gs32/gsweb.cgi?o=dstdcdr&s=id=%22GN0696420337%22.&%22.id.&http://rportal.lib.ntnu.edu.tw:80/handle/20.500.12235/100708我們發展一種新的氧釩金屬錯合物來進行立體選擇性的glycosylation，我們利用糖類的中間體 (glycosyl trichloroacetimidate)在氧釩金屬錯合物的催化下，利用很少的催化劑量，在室溫及溫和的反應條件下，即可以得到高的產率與高的立體選擇性的醣苷產物。我們製備一系列由乙醯基保護的官能基在半乳糖上，也製備一系列有不同官能基保護的糖類，如半乳糖、葡萄糖和岩藻糖。最後我們實驗的結果顯示，使用VO(OTf)2 ( 5 mol% )即可以有效的催化反應的進行。我們利用1o-3o醇、包括脂肪族、芳香族的醇類、硫醇類和氮上有Fmoc保護基的胺基酸 (絲胺酸和半胱胺酸) 進行催化反應，發現這個反應相當溫和不會破壞糖類上的保護基，例如: acetyl, acetonide, Fmoc和酸類衍生的保護官能基。因此這個反應可以提供更多樣化的選擇運用在雙糖和glycopeptides合成上，也可以比以往的路易士酸催化反應得到更高的選擇性與產率。反應進一步的應用在glycosyl azides的合成上，更可以得到幾乎為單一產物的β form glycosyl azide，透過這個方法我們可以很有效率的得到氮連結的醣苷產物，並且將這個新的方法運用在氮連結醣苷化合物 (N-glycosides) 的衍生物上。A new method for stereoselective glycosylation with glycosyl trichloroacetimidate donors employing Oxovanadium(V) complexes, VO(OTf)2 as catalysts is described. This reaction is highly stereoselective and proceeds under mild condition with low catalyst loading in excellent yield at room temperature. We have also prepared a series of functional protecting saccharides such as: galactose, glucose and fucose. Our results have shown that VO(OTf)2 (5 mol%) is the most efficient catalyst with several alcohols (primary, secondary and tertiaryl), including aromatic alcohols, aliphatic alcohols, thiols and Fmoc-protected amino acicds (serine and cysteine). The reactions also tolerate acetal, acetonide, Fmoc, and acid functional groups. Thus, it can be readily catalysted to provide access to a variety of disaccharides and glycopeptides in good yields with highly stereoselectivity product under mild conditions, and then this method may provide a useful route to generate glycosyl azides from isolated oligosaccharides for the formation of novel N–linked glycoconjugates.醣苷化反應氧釩金屬錯合物Glycosylation