Electrophilic Activation of Iodonium Ylides by Halogen-Bond-Donor Catalysis for Cross-Enolate Coupling
作者:Masato Saito、Yusuke Kobayashi、Seiji Tsuzuki、Yoshiji Takemoto
DOI:10.1002/anie.201703641
日期:2017.6.19
The umpolung alkylation of silyl enol ethers with an iodonium(III) ylide proceeds under mild conditions to afford various 1,4-dicarbonyl compounds in high yields in the presence of a halogen-bonding catalyst. Unlike typical transition-metal activation processes of such ylide precursors, which tend to proceed via carbenoid intermediates, experimental and computational studies indicate that halogen bonding
甲硅烷基烯醇醚与碘鎓(III)内鎓盐的烷基酚烷基化在温和的条件下进行,从而在卤素键合催化剂的存在下以高收率得到各种1,4-二羰基化合物。与此类内酰胺前体的典型过渡金属活化过程(通常通过类胡萝卜素中间体进行)不同,实验和计算研究表明XB供体催化剂和碘鎓内鎓盐之间的卤素键(XB)在促进反应中起关键作用。相容的布朗斯台德碱催化剂的鉴定使得该方法能够扩展到就地生成的烯醇,从而以高收率得到相应的加合物。