Sustainable Palladium-Catalyzed Tsuji–Trost Reactions Enabled by Aqueous Micellar Catalysis
作者:Nicholas R. Lee、Farbod A. Moghadam、Felipe C. Braga、Daniel J. Lippincott、Bingchun Zhu、Fabrice Gallou、Bruce H. Lipshutz
DOI:10.1021/acs.orglett.0c01329
日期:2020.7.2
reactions, can be run under micellarcatalysis conditions featuring not only chemistry in water but also numerous combinations of reaction partners that require low levels of palladium, typically on the order of 1000 ppm (0.1 mol %). These couplings are further characterized by especially mild conditions, leading to a number of cases not previously reported in an aqueous micellar medium. Inclusion of diverse
作者:Preiss, A.、Dietzel, St.、Fedgenhaeuer, H.、Hesse, B.
DOI:——
日期:——
An Efficient Diastereoselective Reduction of α-Alkyl-β-keto Carbonitriles with TiCl4/BH3 or LiBH4/CeCl3 to syn- or anti-α-Alkyl-β-hydroxy Carbonitriles
作者:Renato Dalpozzo、Giuseppe Bartoli、Marcella Bosco、Antonio De Nino、Antonio Procopio、Letizia Sambri、Antonio Tagarelli
alpha -Alkyl-beta -keto carbonitriles can be reduced stereoselectively to syn- and anti-alpha -alkyl-beta -hydroxy carbonitriles. The stereoselectivity can be explained in terms of properties of the Lewis acid employed. TiCl4 in noncoordinating solvents such as dichloromethane, followed by reduction with the borane/pyridine complex, predominantly led to the syrz-alpha -alkyl-beta -hydroxy carbonitriles, according to a chelate transition state, whereas CeCl3 in coordinating solvents such as THF, followed by reduction with LiBH4, predominantly led to the anti-isomers, in agreement with an open-chain transition state. The reduction to syn-alpha -alkyl-beta -hydroxy carbonitriles is the first general preparation of these compounds.