Department of Chemistry, University of Wisconsin, 1101 University Avenue, Madison, Wisconsin 53706, USA.
J Am Chem Soc. 2012 Oct 3;134(39):16131-4. doi: 10.1021/ja306446m. Epub 2012 Sep 19.
A Cu(I)-catalyzed 1,3-halogen migration reaction effectively recycles an activating group by transferring bromine or iodine from a sp(2) to a benzylic carbon with concomitant borylation of the Ar-X bond. The resulting benzyl halide can be reacted in the same vessel under a variety of conditions to form an additional carbon-heteroatom bond. Cross-over experiments using an isotopically enriched bromide source support intramolecular transfer of Br. The reaction is postulated to proceed via a Markovnikov hydrocupration of the o-halostyrene, oxidative addition of the resulting Cu(I) complex into the Ar-X bond, reductive elimination of the new sp(3) C-X bond, and final borylation of an Ar-Cu(I) species to turn over the catalytic cycle.
一种 Cu(I)催化的 1,3-卤代迁移反应，通过从 sp(2)碳原子向苄基碳原子转移溴或碘，有效地实现了活化基团的循环，并伴随着 Ar-X 键的硼化。所得的苄基卤化物可以在同一容器中在多种条件下反应，形成另外的碳-杂原子键。使用同位素富集的溴化物源的交叉实验支持 Br 的分子内转移。该反应被假定通过邻卤代苯乙烯的 Markovnikov 氢加成、所得 Cu(I)配合物向 Ar-X 键的氧化加成、新的 sp(3) C-X 键的还原消除以及最终的 Ar-Cu(I)物种的硼化来进行，从而使催化循环翻转。
