82032-17-5Relevant academic research and scientific papers
Allylic C-H Alkynylation via Copper-Photocatalyzed Cross-Dehydrogenative Coupling
Almasalma, Ahmad A.,Mejía, Esteban
, p. 529 - 536 (2020/02/13)
An efficient, novel photocatalyzed allylic-alkynylation methodology via copper-based cross-dehydrogenative coupling (CDC) is described. Different types of 1,4-enyne compounds were synthesized in one step at room temperature using copper(I) terpyridyl comp
(Guanidine)copper Complex-Catalyzed Enantioselective Dynamic Kinetic Allylic Alkynylation under Biphasic Condition
Cui, Xi-Yang,Ge, Yicen,Tan, Siu Min,Jiang, Huan,Tan, Davin,Lu, Yunpeng,Lee, Richmond,Tan, Choon-Hong
supporting information, p. 8448 - 8455 (2018/06/22)
Highly enantioselective allylic alkynylation of racemic bromides under biphasic condition is furnished in this report. This approach employs functionalized terminal alkynes as pro-nucleophiles and provides 6- and 7-membered cyclic 1,4-enynes with high yields and excellent enantioselectivities (up to 96% ee) under mild conditions. Enantioretentive derivatizations highlight the synthetic utility of this transformation. Cold-spray ionization mass spectrometry (CSI-MS) and X-ray crystallography were used to identify some catalytic intermediates, which include guanidinium cuprate ion pairs and a copper-alkynide complex. A linear correlation between the enantiopurity of the catalyst and reaction product indicates the presence of a copper complex bearing a single guanidine ligand at the enantio-determining step. Further experimental and computational studies supported that the alkynylation of allylic bromide underwent an anti-SN2′ pathway catalyzed by nucleophilic cuprate species. Moreover, metal-assisted racemization of allylic bromide allowed the reaction to proceed in a dynamic kinetic fashion to afford the major enantiomer in high yield.
Copper-Catalyzed Allylic C?H Alkynylation by Cross-Dehydrogenative Coupling
Almasalma, Ahmad A.,Mejía, Esteban
supporting information, p. 12269 - 12273 (2018/08/28)
C?H bond functionalization is a well-developed concept that has been thoroughly studied and gives entry to rather complex molecules without the need for previous derivatization of the substrates. The use of copper complexes in allylic C?H bond functionalization under oxidative conditions as an alternative to the well-established palladium-based methodologies remains largely underdeveloped. Here, we show for the first time a selective cross-dehydrogenative coupling reaction between underivatized allylic substrates and terminal alkynes to produce 1,4-enynes in high yields in a single step, using an in situ synthesized copper catalyst and an oxidant.
Vinyl Cations, 37. Rearrangement of Cyclic Homopropargyl Sulfonates to Condensed Cyclobutanones and Cyclopropyl Ketones
Hanack, Michael,Schuhmacher, Werner,Kunzmann, Erich
, p. 1467 - 1487 (2007/10/02)
Cyclic homopropargyl sulfonates 8 (tosylates, triflates, nonaflates, and damsylates) are prepared and solvolysed.The resulting rearrangement reactions are studied with respect to the properties of the solvents used, leaving groups, the substituent on the triple bond, and with respect to the ring size of the sulfonates 8.
