Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Фев. 5, 2025

The regio- and stereoselective hydroalkynylation of internal alkynes with terminal is great interest importance as a straightforward route for synthesizing multisubstituted 1,3-enynes. However, this transformation often suffers from stereoselectivity issues when working unsymmetrical alkynes. Herein, we report the first time syn-stereoselective variety heteroatom-functionalized including homopropargyl ethers, thioethers, tertiary amines by half-sandwich rare-earth catalysts. This protocol provides an atom-efficient synthesis new family heteroatom (O, S, or N)-functionalized 1,3-enynes, featuring 100% atom-efficiency, broad substrate scope, high syn-stereoselectivity (>19:1 r.r. >19:1 syn/anti). mechanistic details have been elucidated deuterium-labeling experiments, control isolation transformations key reaction intermediates, revealing that proceeded through C(sp)–H deprotonation alkyne scandium alkyl species to form catalytically active dimeric tetraalkynyl followed heteroatom-assisted insertion into Sc–alkynyl bond subsequent protonolysis resulting Sc–alkenyl another molecule. coordination N) catalyst metal center plays critically important role in achieving level reactivity stereoselectivity. Remarkably, can be recovered reused, constituting example recyclable system

Язык: Английский