Transition‐Metal‐Free Reductive Functionalization of Tertiary Carboxamides and Lactams for α‐Branched Amine Synthesis
作者:Derek Yiren Ong、Dongyang Fan、Darren J. Dixon、Shunsuke Chiba
DOI:10.1002/anie.202004272
日期:2020.7.13
A new method for the synthesis of α‐branched amines by reductive functionalization of tertiary carboxamides and lactams is described. The process relies on the efficient and controlled reduction of tertiary amides by a sodium hydride/sodiumiodide composite, in situ treatment of the resulting anionic hemiaminal with trimethylsilyl chloride and subsequent coupling with nucleophilic reagents including
New protocols for controlled reduction of carboxamides to either alcohols or amines were established using a combination of sodium hydride (NaH) and zinc halides (ZnX2). Use of a different halide on ZnX2 dictates the selectivity, wherein the NaH‐ZnI2 system delivers alcohols and NaH‐ZnCl2 gives amines. Extensive mechanistic studies by experimental and theoretical approaches imply that polymeric zinc
Palladium-Catalyzed Intramolecular Asymmetric C–H Functionalization/Cyclization Reaction of Metallocenes: An Efficient Approach toward the Synthesis of Planar Chiral Metallocene Compounds
synthesis of planar chiral metallocene compounds is reported. The reaction stereoselectively functionalized one of the ortho C-H bonds of Cp rings by intramolecular cyclization to form indenone derivatives in high yields with excellent enantioselectivity. The mild set of reaction conditions allowed a wide variety of chiral metallocene compounds to be synthesized with broad functional group tolerance. The
BF<sub>3</sub>·OEt<sub>2</sub>-Promoted Synthesis of 2,3-Metallocenocyclohexanones: A 1,2-Hydride Shift and Cationic Cyclization Strategy
作者:Congfa He、Jie Wang、Zhenhua Gu
DOI:10.1021/acs.joc.5b01511
日期:2015.8.21
is reported. 2,3-Metallocenocyclohexanones were formed exclusively, and no normal Nazarov-type cyclopentanone analogues were detected. The reaction possibly proceeded via an unusual cationic 1,2-hydrideshift followed by Friedel–Crafts alkylative cyclization process. During the studies of the alkylation reaction of these keto esters, an unusual and rare facial selectivity was observed. The electrophiles
Highly efficient reduction of ferrocenyl derivatives by borane
作者:Lucie Routaboul、Jérôme Chiffre、Gilbert G.A. Balavoine、Jean-Claude Daran、Eric Manoury
DOI:10.1016/s0022-328x(01)00936-6
日期:2001.12
Borane, as a DMS or a THF complex, can efficiently reduce a large range of ferrocenyl derivatives (aldehydes, ketones, ethers, acetals, carboxylic acids, esters,…) if they bear at least one oxygen at a carbon at the α position. On the contrary, similar molecules, which contain nitrogen instead of oxygen, do not react with borane.