| Literature DB >> 24474558 |
Ming Joo Koh1, R Kashif M Khan, Sebastian Torker, Amir H Hoveyda.
Abstract
A broadly applicable Ru-catalyzed protocol for Z-selective ring-opening/cross-metathesis (ROCM) is disclosed. In addition to reactions relating to terminal alkenes of different sizes, the first examples of Z-selective ROCM processes involving heteroaryl olefins, 1,3-dienes, and O- and S-substituted alkenes as well as allylic and homoallylic alcohols are reported. Z-Selective transformations with an α-substituted allylic alcohol are shown to afford congested Z alkenes with high diastereoselectivity. Transformations are performed in the presence of 2.0-5.0 mol % of a recently disclosed Ru-based dithiolate complex that can be easily prepared in a single step from commercially available starting materials. Typically, transformations proceed at ambient temperature and are complete within eight hours; products are obtained in up to 97 % yield, >98:2 Z/E, and >98:2 diastereomeric ratio. The present investigations reveal a mechanistically significant attribute of the Ru-based dithiolates that arises from electrostatic interactions with anionic S-based ligands.Entities:
Keywords: alkenes; olefin metathesis; ring-opening/cross-metathesis; ruthenium; synthetic methods
Year: 2014 PMID: 24474558 DOI: 10.1002/anie.201309430
Source DB: PubMed Journal: Angew Chem Int Ed Engl ISSN: 1433-7851 Impact factor: 15.336