employing commercially available Ni(η2-1,5-cyclooctadiene)2 as the catalyst. A series of biologically interesting cyclic products were afforded in moderate to excellent yields with high regio- and diastereoselectivities.
biphenyl phosphoramidites bearing a D2-symmetric biphenyl backbone was prepared and applied as chiral ligands in the copper-catalyzedallylicalkylation with Grignard reagent. The alkylation products were obtained in quantitative yields with high regioselectivities up to 94:6 of SN2′/SN2 ratio and enantiomeric excesses up to 91.1% for SN2′ products. The unique D2-symmetric backbone ligands have the
制备了一类新型的具有D 2-对称联苯骨架的对映体双桥联苯二亚磷酰胺,并将其用作手性配体,用格氏试剂在铜催化的烯丙基烷基化反应中使用。烷基化产物以定量产率获得,具有高达S N 2'/ S N 2之比的94:6的高区域选择性,并且对于S N 2'产物,对映体过量高达91.1%。独特的D 2-对称主链配体的优点是易于制备,并且其关键中间体可以从不希望的异构体中充分利用。
Highly Regio- and Enantioselective Hydrogenation of Conjugated α-Substituted Dienoic Acids
Highly regio- and enantioselective hydrogenation of conjugated α-substituted dienoic acids was realized for the first time using Trifer–Rh complex, providing a straightforward method for the synthesis of chiral α-substituted γ,δ-unsaturated acids. DFT calculations revealed N+H–O hydrogen bonding interaction is formed to stabilize the transition state and the coordination of 4,5-double bond to Rh(III)
1,2,4-Trifunctionalized Cyclohexane Synthesis via a Diastereoselective Reductive Cope Rearrangement and Functional Group Interconversion Strategy
作者:Michael D. Mannchen、Ion Ghiviriga、Khalil A. Abboud、Alexander J. Grenning
DOI:10.1021/acs.orglett.1c03310
日期:2021.11.19
Polyfunctionalized cyclohexanes are privileged scaffolds in drug discovery. Reported herein is a method for synthesizing 1,2,4-trifunctionalized cyclohexanes via diastereoselective reductive Cope rearrangement. The scaffolds obtained can be derivatized by orthogonal functional group interconversion to cyclohexanes bearing a 1-amide, 2-branched arylallyl, and variable 4-functional group.
Enantioselective Sulfonium–Claisen Rearrangement with Cinnamyl Thioethers
作者:Jiwon Jang、Youngjin Bae、Seunghoon Shin
DOI:10.1021/acs.orglett.3c01244
日期:2023.6.2
Sulfonium–Claisen rearrangement leveraged by the gold-catalyzed formation of allyl sulfonium intermediates has enabled an exceptional level of regio- and enantiocontrol for the synthesis of skipped 1,4-dienes. However, the application of cinnamyl thioether derivatives to the sulfonium–Claisen rearrangement has been unsuccessful so far due to the extensive dissociation of the cinnamyl cation. By fine-tuning