Enantioselective bromolactonization of conjugated (Z)-enynes.
نویسندگان
چکیده
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.
منابع مشابه
DABCO-catalyzed 1,4-bromolactonization of conjugated enynes: highly stereoselective formation of a stereogenic center and an axially chiral allene.
A DABCO-catalyzed highly regio- and stereoselective syn-1,4-bromolactonization of conjugated enynes was discovered. The 1,4-addition occurred selectively over 1,2-addition for most enynes. In contrast to anti 1,2-addition to alkenes, where two adjacent stereogenic centers are created, 1,4-addition across conjugated enynes can produce a stereogenic center and an axially chiral allene simultaneou...
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ورودعنوان ژورنال:
- Journal of the American Chemical Society
دوره 132 11 شماره
صفحات -
تاریخ انتشار 2010