title: Rare-earth silylamide-catalyzed monocoupling reaction of isocyanides with terminal alkynes.
abstract: [reaction: see text] Rare-earth silylamides, Ln[N(SiMe3)2]3 (Ln = Y, La, Sm, Yb), serve as good catalysts for monoinsertion of isocyanides into terminal alkynes in the presence of amine additives, leading to 1-aza-1,3-enyens in excellent yields. The reaction is applicable to a diverse set of terminal alkynes with various functionalities such as ethers, acetals, and amino groups. Larger metals (La and Sm) give a better performance than smaller ones (Y and Yb). Using less hindered primary amines and, in contrast, bulky isocyanides is crucial for the coupling reaction; otherwise, competitive oligomerization of the isocyanides occurs predominantly. In the mechanistic study, the rate-determining step of the reaction seems to be the first insertion of the isocyanides into rare-earth alkynides, which is followed by spontaneous protonation with the amine additives.
authors.affiliation: Department of Chemistry and Chemical Engineering, Graduate School of Engineering, Hiroshima University, Kagamiyama, Higashi-Hiroshima 739-8527, Japan. kkome@hiroshima-u.ac.jp
authors.forename: Kimihiro
authors.initials: K
authors.lastname: Komeyama
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sasayama
authors.forename: Tomonori
authors.initials: T
authors.lastname: Kawabata
authors.forename: Katsuomi
authors.initials: K
authors.lastname: Takehira
authors.forename: Ken
authors.initials: K
authors.lastname: Takaki