A Doubly Axially Chiral Phosphoric Acid Catalyst for the Asymmetric Tandem Oxyfluorination of Enamides
作者:Takashi Honjo、Robert J. Phipps、Vivek Rauniyar、F. Dean Toste
DOI:10.1002/anie.201205383
日期:2012.9.17
Double agent: Enantioselective tandemoxyfluorination of enamides using a doublyaxiallychiralphosphoricacidcatalyst is reported. The chiralphosphoricacidcatalyst controls both a fluorination step, using a chiral anion phase‐transfer strategy, and addition to the resulting imine under the guise of Brønsted acid catalysis.
anti-Markovnikov addition of primary amides to terminalalkynes under the formation of Z-configured secondaryenamides is efficiently promoted by a catalyst system generated in situ from bis(2-methallyl)(cycloocta-1,5-diene)ruthenium(II), 1,4-bis(dicyclohexylphosphino)butane, and ytterbium triflate. The thermodynamically more stable E-isomers are accessible by combining the above hydroamidation with an in