Koo Bonsuk, McDonald Frank E
Department of Chemistry, Emory University, Atlanta, Georgia 30322, USA.
Org Lett. 2007 Apr 26;9(9):1737-40. doi: 10.1021/ol070435s. Epub 2007 Mar 27.
[reaction: see text] The tungsten-catalyzed cycloisomerization of alkynyl alcohols can be conducted without using photochemistry, using a stable tungsten Fischer carbene as the precatalyst for this transformation. A variety of alkynyl alcohols undergo cycloisomerization under these conditions to provide endocyclic enol ethers of five-, six-, and seven-membered ring sizes. The utility of this method is further demonstrated in the stereoselective synthesis of the disaccharide substructure of altromycin B.
[反应:见正文] 炔醇的钨催化环异构化反应无需使用光化学方法即可进行,使用稳定的钨费歇尔卡宾作为该转化反应的预催化剂。多种炔醇在这些条件下发生环异构化反应,生成五元、六元和七元环大小的环内烯醇醚。该方法的实用性在阿洛霉素B二糖亚结构的立体选择性合成中得到了进一步证明。