Sterically Demanding Oxidative Amidation of α-Substituted Malononitriles with Amines Using O<sub>2</sub>
作者:Jing Li、Martin J. Lear、Yujiro Hayashi
DOI:10.1002/anie.201603399
日期:2016.7.25
An efficient amidation method between readily available 1,1-dicyanoalkanes and either chiral or nonchiral amines was realized simply with molecular oxygen and a carbonate base. This oxidative protocol can be applied to both sterically and electronically challenging substrates in a highly chemoselective, practical, and rapid manner. The use of cyclopropyl and thioether substrates support the radical
Overcoming Selectivity Issues in Reversible Catalysis: A Transfer Hydrocyanation Exhibiting High Kinetic Control
作者:Benjamin N. Bhawal、Julia C. Reisenbauer、Christian Ehinger、Bill Morandi
DOI:10.1021/jacs.0c03184
日期:2020.6.24
Reversible catalytic reactions operate under thermodynamic control and thus establishing a selective catalytic system poses a considerable challenge. Herein, we report a reversible transfer hydrocyanation protocol that exhibits high selectivity for the thermodynamically less favorable branched isomer. Selectivity is achieved by exploiting the lower barrier for C-CN oxidative addition and reductive elimination
Enantioselective Synthesis of Fused Isocoumarins via Palladium-Catalyzed Annulation of Alkyne-Tethered Malononitriles
作者:Hui Zhang、Weishuang Li、Xu-Dong Hu、Wen-Bo Liu
DOI:10.1021/acs.joc.1c01026
日期:2021.8.6
An enantioselective palladium-catalyzed annulation of alkyne-tethered malononitriles for the synthesis of 3,4-ring-fused isocoumarins is described. This cascade strategy involves oxypalladation of ortho-alkynylbenzoates and desymmetrizing addition onto one cyano group of the pendant malononitriles, which enables the concurrent construction of two rings and an all-carbon quaternary stereocenter in a
Sodium Borohydride as the Only Reagent for the Efficient Reductive Alkylation of Malononitrile with Ketones and Aldehydes
作者:Robert E. Sammelson、Jason C. Dunham、Adam D. Richardson
DOI:10.1055/s-2006-926307
日期:——
malononitriles has been developed. In this method, sodium borohydride in isopropanol has a catalytic effect on the initial condensation between malononitrile and aldehydes or ketones at 0 °C. The sodium borohydride also simultaneously acts as a reagent and reduces the unsaturated intermediate formed in situ by the condensation. This simple reductive alkylation method effectively consumes all malononitrile
condensation–reduction approach, which was carried out in water, has been reported. Using Hantzsch esters as reducing agent, under the promotion of base, a variety of reduced Knoevenagel adducts could be easily prepared by direct alkylation of malononitrile, ethyl 2-cyanoacetate, and 2-(4-nitrophenyl)acetonitrile, respectively. Meanwhile, a gram-scale synthesis of the protocol was also realized with excellent