Chemoselective Reduction of Sterically Demanding <i>N</i>,<i>N</i>-Diisopropylamides to Aldehydes
作者:Peihong Xiao、Zhixing Tang、Kai Wang、Hua Chen、Qianyou Guo、Yang Chu、Lu Gao、Zhenlei Song
DOI:10.1021/acs.joc.7b02868
日期:2018.2.16
EtOTf and LiAlH(OEt)3 in the absence of base were found to be optimal for reducing extremely sterically demanding 2,6-disubstituted N,N-diisopropylbenzamides. The reaction tolerates various reducible functional groups, including aldehyde and ketone. 1H NMR studies confirmed the formation of imidates stable in water. The synthetic usefulness of this methodology was demonstrated with N,N-diisopropylamide-directed
Pd-catalyzed C-H functionalizations promoted by transientdirectinggroups remain largely limited to C-H arylation only. Herein, we report a diverse set of ortho-C(sp2)-H functionalizations of benzaldehyde substrates using the transientdirectinggroup strategy. Without installing any auxiliary directinggroup, Pd(II)-catalyzed C-H arylation, chlorination, bromination, and Ir(III)-catalyzed amidation
New cyclopentadienyl, indenyl or fluorenyl substituted phosphine compounds and their use in catalytic reactions
申请人:Evonik Degussa GmbH
公开号:EP1894938A1
公开(公告)日:2008-03-05
The invention is directed to a phosphine compound represented by general formula (1)
wherein
R' and R" independently are selected from alkyl, cycloalkyl and 2-furyl radicals, or R' and R" are joined together to form with the phosphorous atom a carbon-phosphorous monocycle comprising at least 3 carbon atoms or a carbon-phosphorous bicycle; the alkyl radicals, cycloalkyl radicals, and carbon-phosphorous monocycle being unsubstituted or substituted by at least one radical selected from the group of alkyl, cycloalkyl, aryl, alkoxy, and aryloxy radicals;
Cps is a partially substituted or completely substituted cyclopentadien-1-yl group, including substitutions resulting in a fused ring system, and wherein a substitution at the 1-position of the cyclopentadien-1-yl group is mandatory when the cyclopentadien-1-yl group is not part of a fused ring system or is part of an indenyl group. Also claimed is the use of these phosphines as ligands in catalytic reactions and the preparation of these phosphines.
9-Fluorenylphosphines for the Pd-Catalyzed Sonogashira, Suzuki, and Buchwald–Hartwig Coupling Reactions in Organic Solvents and Water
作者:Christoph A. Fleckenstein、Herbert Plenio
DOI:10.1002/chem.200601142
日期:2007.3.16
lithiation and reaction with R2PCl (R=Cy, iPr, tBu) generates 9-alkyl, 9-PR2-fluorenes which constitute electron-rich and bulky phosphine ligands. The in-situ-formed palladium-phosphine complexes ([Na2PdCl4], phosphonium salt, base, substrates) were tested in the Sonogashira, Suzuki, and Buchwald-Hartwig reactions of aryl chlorides and arylbromides in organic solvents. The Sonogashira coupling of aryl chlorides
Phosphino Hydrazones as Suitable Ligands in the Asymmetric Suzuki–Miyaura Cross-Coupling
作者:Abel Ros、Beatriz Estepa、Antonio Bermejo、Eleuterio Álvarez、Rosario Fernández、José M. Lassaletta
DOI:10.1021/jo300548z
日期:2012.5.18
Phosphino hydrazones derived from C2-symmetric hydrazines exhibit excellent catalytic activity and provide good enantioselectivities in the asymmetric Suzuki–Miyaura cross-coupling to axially chiralbiaryls, in particular for the most challenging reactions of monocyclic, functionalized aryl bromides and triflates. X-ray analysis of preformed [Pd(P/N)Cl2] precatalysts [(P/N) = phosphino hydrazone] revealed