Concise and Practical Synthesis of <i>C</i>-Glycosyl Ketones from Sugar Benzothiazoles and Their Transformation into Chiral Tertiary Alcohols
作者:Alessandro Dondoni、Nicola Catozzi、Alberto Marra
DOI:10.1021/jo051377w
日期:2005.11.1
deoxygenation, were subjected to a one-pot reaction sequence involving N-methylation of the heterocyclic ring by MeOTf, treatment of the N-methylbenzothiazolium salt with a Grignard reagent, and HgCl2-promoted hydrolysis of the benzothiazoline thus formed. The resulting ketones were isolated in yields varying from 35 to 80%. Treatment of the sugar ketones with various organometals containing the phenyl
13吨不对称酮的集合,每一个设有一个糖(d -glucosyl,d半乳糖,d -mannosyl,和升-fucosyl)和糖苷配基部分(苯基,2-噻唑基,TMS乙炔基,烯丙基,和1-丙烯基)是通过使用苯并噻唑作为羰基当量的均一路线制备的。简洁地说,Ç -glycosylbenzothiazoles容易地通过加入2- lithiobenzothiazole糖内酯和脱氧的制备,进行涉及一锅反应序列Ñ通过MeOTf,治疗的杂环的-methylation Ñ -methylbenzothiazolium盐与格氏试剂和HgCl 2促进了由此形成的苯并噻唑啉的水解。分离得到的酮,产率为35%至80%。用含有苯基,2-噻唑基,TMS-乙炔基或乙炔基作为取代基的各种有机金属处理糖酮,得到手性叔醇。如通过粗NMR分析观察到的,这些加成反应是高度立体选择性的,并且在每种情况下都以高产率分离出单个差向异构体。然