The enantioselective construction of all-carbon quaternary stereocenters on α-acyl-γ-butyrolactones has been achieved by the N-spiro chiral quaternary ammonium bromide 1-catalyzed alkylation under mild phase-transfer conditions. The resulting α-alkylated keto lactones serve as valuable chiral building blocks in organic synthesis as clearly demonstrated by the facile conversion to optically active α
A Pd-Catalyzed Synthesis of Functionalized Piperidines
作者:Benjamin D. W. Allen、Matthew J. Connolly、Joseph P. A. Harrity
DOI:10.1002/chem.201602586
日期:2016.9.5
A readily available cyclic carbamate 1 functions as a general precursor to a range of functionalized piperidine products via a new Pd‐catalyzed annulation strategy. An asymmetric catalytic variant provides a rapid and efficient means to access these heterocycles with high to excellent levels of enantiocontrol. Finally, these richly functionalized compounds are amenable to further chemoselective elaboration
Enantioselective Organocatalytic Diels Aminations: α-Aminations of Cyclic β-Keto Esters and β-Keto Lactones with Cinchonidine and Cinchonine
作者:Petri M. Pihko、Antti Pohjakallio
DOI:10.1055/s-2004-831326
日期:——
Catalytic enantioselective α-amination reactions of β-keto esters and β-keto lactones with dibenzyl azodicarboxylate are catalyzed by cinchona alkaloids, affording the products in up to 99% yield and 90% ee.
A Three-Component Palladium-Catalyzed Oxidative CC Coupling Reaction: A Domino Process in Two Dimensions
作者:Roshan Y. Nimje、Mikko V. Leskinen、Petri M. Pihko
DOI:10.1002/anie.201300833
日期:2013.4.26
Easy as ABC…︁ or CBA! Indoles can be selectively functionalized twice by a catalytic oxidative three‐component coupling of arylboronates and β‐ketoesters. The difference in the rates (see scheme) of the competing processes are amplified under the conditions of the three‐component reaction.
Palladium-Catalyzed Dehydrogenative β′-Functionalization of β-Keto Esters with Indoles at Room Temperature
作者:Mikko V. Leskinen、Kai-Tai Yip、Arto Valkonen、Petri M. Pihko
DOI:10.1021/ja300684r
日期:2012.4.4
The dehydrogenative beta'-functionalization of a-substituted beta-keto esters with indoles proceeds with high regioselectivities (C3-selective for the indole partner and beta'-selective for the beta-keto ester) and good yields under mild palladium catalysis at room temperature with a variety of oxidants. Two possible mechanisms involving either late or early involvement of indole are presented.