A novel ruthenium catalyst is introduced which contains solely achiral ligands and acquires its chirality entirely from octahedral centrochirality. The configurationally stable catalyst is demonstrated to catalyze the alkynylation of trifluoromethyl ketones with very high enantioselectivity (up to >99% ee) at low catalyst loadings (down to 0.2 mol%).
Copper(I) Alkoxide-Catalyzed Alkynylation of Trifluoromethyl Ketones
作者:Rie Motoki、Motomu Kanai、Masakatsu Shibasaki
DOI:10.1021/ol071003k
日期:2007.8.1
A general method for direct alkynylation of trifluoromethyl ketones was developed by using (CuOBu)-Bu-t-xantphos or phenanthroline complexes as catalysts. The ligands significantly enhanced the catalyst activity. In addition, KOTf, generated in the catalyst preparation step, exhibited some acceleration effects. A preliminary extension to a catalytic enantioselective CF3-substituted tertiary propargyl alcohol synthesis (up to 52% ee) is also described.
Acidic Zeolite-Catalyzed Reaction of 2,4-Diaryl-1,1,1-trifluorobut-3-yn-2-ols with Benzene. A New Synthesis of 1,3-Diaryl-1-trifluoromethylindenes
作者:S. K. Nursahedova、A. V. Zerov、A. V. Vasilyev
DOI:10.1134/s1070428018120047
日期:2018.12
Reactions of 2,4-diaryl-1,1,1-trifluorobut-3-yn-2-ols with benzene in the presence of HUSY acidic zeolite (CBV-720) at 100 degrees C in 1 h (glass high-pressure reactor) led to the formation of 1,3-diaryl-1-trifluoromethylindenes in 39-92% yield. A probable reaction mechanism was proposed, which involves formation of the corresponding trifluoromethyl-substituted propargyl cations.