Application of Electron-Withdrawing Coordinatively Unsaturated η6-Arene β-Diketiminato–Ruthenium Complexes in Lewis Acid Catalyzed Diels–Alder Reactions

Autor:	Helge Müller-Bunz, Andrew D. Phillips, Yannick Ortin, Dominique F. Schreiber
Rok vydání:	2011
Předmět:	Trifluoromethyl Cyclopentadiene Organic Chemistry chemistry.chemical_element Methacrolein Medicinal chemistry Catalysis Ruthenium Inorganic Chemistry Transmetalation chemistry.chemical_compound chemistry Polar effect Organic chemistry Lewis acids and bases Physical and Theoretical Chemistry
Zdroj:	Organometallics. 30:5381-5395
ISSN:	1520-6041 0276-7333
DOI:	10.1021/om200566a
Popis:	Utilizing the aza-Wittig reaction involving the ylid 3,5-(CF3)2C6H3NPPh3 and 1,1,1,5,5,5-hexafluoro-2,4-pentanedione, a highly fluorinated and electron-withdrawing β-diketiminate was obtained. Using strong bases, nBuLi, Ag2O, or TlOEt, the corresponding β-diketiminato-Li, -Ag, or -Tl chelated complexes were prepared. Subsequent in situ transmetalation with (Ru(η6-C6H6)Cl2)2 or (Ru(η6-p-cymene)Cl2)2 afforded the half-sandwich chloro-substituted Ru(II) β-diketimino complexes in high yield. The synthesis of the Lewis acidic catalysts featuring a vacant coordination site at the metal center was accomplished using [Na]BArF (BArF = tetrakis[3,5-bis(trifluoromethyl)phenyl]boron). These complexes are active for the Lewis acid catalyzed Diels–Alder reaction between α,β-unsaturated aldehydes, that is, methacrolein, acrolein, and dienes, that is, cyclopentadiene and 2,3-dimethyl-1,3-butadiene, with conversions in the range of 66–98% under mild conditions. Whereas the herein described catalysts generally promote exo ...
Databáze:	OpenAIRE
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