School of Pharmacy, University of Wisconsin, Madison, Wisconsin 53705, USA.
J Am Chem Soc. 2010 Mar 24;132(11):3664-5. doi: 10.1021/ja100173w.
A catalytic enantioselective syn-1,4-bromolactonization of conjugated (Z)-enynes was reported. Diastereomeric ratios >20:1 and up to 99% enantiomeric excesses were observed. Di-, tri-, and tetra-substituted bromoallenes were prepared together with lactone heterocycles efficiently and stereoselectively. Preliminary investigations suggest that the chiral catalyst may serve as a bifunctional reagent by interacting with both a carboxylic acid nucleophile and NBS electrophile.
报道了一种催化对映选择性的共轭（Z）-烯炔的顺式-1,4-溴内酯化反应。观察到非对映体比例>20:1 和高达 99%的对映体过量。高效立体选择性地制备了二取代、三取代和四取代的溴烯丙基化合物以及内酯杂环化合物。初步研究表明，手性催化剂可能通过与羧酸亲核试剂和 NBS 亲电试剂相互作用，充当双功能试剂。
