(NHC)NiH-Catalyzed Regiodivergent Cross-Hydroalkenylation of Vinyl Ethers with α-Olefins: Syntheses of 1,2- and 1,3-Disubstituted Allyl Ethers
作者:Weihao Chen、Yang Li、Yang Chen、Chun-Yu Ho
DOI:10.1002/anie.201712693
日期:2018.3.1
(i.e., 1 as acceptor and 2 as donor) was controlled mostly by electronic effects through the catalyst–substrate interaction. Sterically bulkier alkenes (2) were used as preferred donors compared to smaller alkenes. This electronic effect also served as a basis for the first tail‐to‐head cross‐hydroalkenylations of 1 with either a vinyl silane or boronic ester.
乙烯基醚(1)与α-烯烃(2)的交叉氢化烯基化首先通过一组[NHC-Ni(烯丙基)] BAr F(NHC = N-杂环卡宾)催化剂实现。通过使用不同尺寸的NHC,可以高度选择性地获得1,2-和1,3-二取代的烯丙基醚。相比之下,化学选择性(即1为受体,2为施主)主要受催化剂与底物相互作用的电子效应控制。与较小的烯烃相比,在立体上较大的烯烃(2)被用作优选的给体。这种电子效应也作为第一尾-头横hydroalkenylations的基础1 与乙烯基硅烷或硼酸酯。