An Efficient and Stereoselective Synthesis of Xerulin <i>via</i> Pd-Catalyzed Cross Coupling and Lactonization Featuring (<i>E</i>)-Iodobromoethylene as a Novel Two-Carbon Synthon
作者:Ei-ichi Negishi、Asaf Alimardanov、Caiding Xu
DOI:10.1021/ol990336h
日期:2000.1.1
[structure: see text] Xerulin, an inhibitor of cholesterol biosynthesis, has been synthesized from commercially available (E)-1-bromopropene, acetylene, and propynoic acid in five steps (longest linear sequence) in 30% overall yield and >96% stereoselectivity. The preparation of (E)-iodobromoethylene and its use in the Pd-catalyzed cross coupling are two of the novel aspects of the synthesis reported
A Strictly “Pair”-Selective Synthesis of Conjugated Diynes via Pd-Catalyzed Cross Coupling of 1,3-Diynylzincs: A Superior Alternative to the Cadiot−Chodkiewicz Reaction
作者:Ei-ichi Negishi、Mitsuhiro Hata、Caiding Xu
DOI:10.1021/ol000270m
日期:2000.11.1
A strictly "pair"-selective synthesis of conjugated diynes viaPd-catalyzed cross coupling of 1,3-diynylzincs is described. This method, like the Cadiot-Chodkiewicz reaction, requires three steps for the synthesis of R(1)Ctbd1;CCtbd1;CR(2) from R(1)Ctbd1;CH, R(2)X, and HCtbd1;CH. However, the high "pair"-selectivity permitting high-yield production of the desired conjugated diynes without separation