AbstractIsocyanide reagents removed residual palladium from palladium‐catalyzed cross‐couplings, to sub‐ppm levels. The results were similar using either Pd(II) or Pd(0) precatalysts. Using the 3‐isocyanopropylated silica gel reagent 1, no chromatography or other treatments were required. The soluble isocyanide potassium isocyanoacetate (KO2CCH2NC) was also found to be highly effective when combined with silica gel chromatography.magnified image
Highly Enantioselective Synthesis of Functionalized Glutarimide Using Oxidative N-Heterocyclic Carbene Catalysis: A Formal Synthesis of (−)-Paroxetine
作者:Arka Porey、Surojit Santra、Joyram Guin
DOI:10.1021/acs.joc.9b00320
日期:2019.5.3
yet highly effective approach toward enantioselective synthesis of trans-3,4-disubstituted glutarimides from readily available starting materials is developed using oxidative N-heterocyclic carbene catalysis. The catalytic reaction involves a formal [3 + 3] annulation between enals and substituted malonamides enabling the production of glutarimide derivatives in a single chemical operation via concomitant
dicarbene palladium(II) complexes and of simple palladium(II) acetate as catalysts for alkyne hydroarylation under liquid‐liquid biphasic conditions involving an ionic liquid as the catalyst‐containing phase is investigated. The results obtained under these conditions, both in terms of activity and selectivity, are compared with those previously obtained under homogeneous conditions. The catalytic efficiency
Palladium(II) complexes with a ligand set made from a chelating N-heterocyclic dicarbene ligand and two weakly coordinating anions (generally introduced in situ upon addition of 2 equiv. of a suitable silver salt) were found to be very active and selective catalysts for the room-temperature hydroarylation of alkynes at low catalyst loading (0.1 mol-%). Moreover, the screening of various strong acids
Boron-Templated Dimerization of Allylic Alcohols To Form Protected 1,3-Diols via Acid Catalysis
作者:S. Hadi Nazari、Kelton G. Forson、Erin E. Martinez、Nicholas J. Hansen、Kyle J. Gassaway、Nathan M. Lyons、Karissa C. Kenney、Gabriel A. Valdivia-Berroeta、Stacey J. Smith、David J. Michaelis
DOI:10.1021/acs.orglett.9b03760
日期:2019.12.6
boron-templated dimerization of allylicalcohols that generates a 1,3-diol product with two stereogenic centers in high yield and diastereoselectivity. This acid-catalyzed reaction is achieved via in situ formation of a boronic ester intermediate that facilitates selective cyclization and formation of a cyclic boronic ester product. High yields are observed with a variety of allylicalcohols, and mechanistic studies
Pd(II)-catalyzed C–H functionalization of nondirected arenes has been realized using an inexpensive and easily accessible type of bidentate S,O-ligand. The catalytic system shows high efficiency in the C–Holefination reaction of electron-rich and electron-poor arenes. This methodology is operationally simple, scalable, and can be used in late-stage functionalization of complex molecules. The broad