Intermolecular photocatalytic hydroaminoalkylation (HAA) of alkenes have emerged as a powerful method for the construction of alkyl amines. Although there are some studies aiming at stereoselective photocatalytic HAA reactions, the alkenes are limited to electrophilic alkenes. Herein, we report a highly regio-, diastereo-, and enantioselective HAA of electron-rich dienol ethers and α-amino radicals derived from α-amino acids using a unified photoredox and palladium catalytic system. This decarboxylative 1,2-Markovnikov addition enables the construction of vicinal amino tertiary ethers with high levels of regio- (up to >19 : 1 rr), diastereo- (up to >19 : 1 dr), and enantioselectivity control (up to >99 % ee). Mechanistic studies support a reversible hydropalladation as a key step.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9314026 | PMC |
http://dx.doi.org/10.1002/anie.202200105 | DOI Listing |
Chem Commun (Camb)
December 2024
Department of Chemistry, Indian Institute of Technology Jammu, Jagti, NH-44, Nagrota Bypass, Jammu 181221, J&K, India.
A highly regio-, enantio- and diastereo-selective strategy involving initial enantioselective conjugate addition to 4-nitro-5-styrylisoxazoles serves as a key step for the desymmetrization of 2,5-cyclohexadienones has been disclosed. We have designed a new class of 2,5-cyclohexadienones appended with 4-nitro-5-styrylisoxazoles to undergo organocatalytic asymmetric double or triple conjugate addition in a domino sequence depending on the substrate type leading to desymmetrization of the 2,5-cyclohexadienone core. The developed protocol allows the construction of a valuable hydrophenanthrene core or a unique bridged scaffold bearing multiple chiral centers with excellent enantio- (up to >99.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Shanghai Institute of Organic Chemistry, State Key Lab of Organometallic Chemistry, 345 Lingling Road, 200032, Shanghai, CHINA.
A dual photoredox/cobalt-catalyzed protocol for chemo-, regio-, diastereo- and enantioselective reductive coupling of 1,1-disubstituted allenes and cyclobutenes through chemo-, regio-, diastereo- and enantioselective oxidative cyclization followed by stereoselective protonation promoted by a chiral phosphine-cobalt complex is presented. Such process represents an unprecedented reaction pathway for cobalt catalysis that enables selective transformation of the less sterically congested alkenes of 1,1-disubstituted allenes with cyclobutenes, incorporating a broad scope of tetrasubstituted alkenes into the cyclobutane scaffolds in up to 86% yield, >98:2 chemo- and regioselectivity, >98:2 dr and >99.5:0.
View Article and Find Full Text PDFOrg Lett
December 2024
School of Chemistry and Xi'an Key Laboratory of Sustainable Energy Materials Chemistry, Xi'an Jiaotong University, Xi'an 710049, P. R. China.
Herein, we report a DMAP-catalyzed [4 + 2] annulation reaction of hex-5-en-2-ynoates with electron-poor alkenes , which affords exocyclic olefinic cyclohexenes in good yields and excellent regio-, diastereo-, and / selectivities. Distinguished from previous allenoate- or alkynoate-based substrates, hex-5-en-2-ynoates use the β- and ε-carbons for the bond formation, presenting new and regiodivergent C synthons for Lewis base-catalyzed annulations.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 37673, Republic of Korea.
We report a copper-catalyzed regio-, diastereo-, and enantioselective allylic alkylation of allyl bromides using 1,1-diborylalkanes as prochiral nucleophiles. This methodology employs copper(I) bromide as a catalyst, an ()-BINOL-derived phosphoramidite as a ligand, and lithium benzoate as a crucial additive. The reaction affords enantioenriched homoallylic boronic esters possessing vicinal stereocenters in good yields and high diastereo- and enantioselectivity.
View Article and Find Full Text PDFOrg Lett
December 2024
Institute for Advanced and Applied Chemical Synthesis, College of Pharmacy, State Key Laboratory of Bioactive Molecules and Druggability Assessment, Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM & New Drugs Research, Jinan University, Guangzhou 510632, Guangdong, China.
This paper describes an iridium-catalyzed allylation of ring-fused pyrazolones that proceeds with excellent regio-, diastereo- and enantio-selectivities. The approach exploits unactivated, racemic allylic alcohols as a source of allyl building blocks. Asymmetric syntheses of a series of biologically relevant, chiral pyrazolones highlight the utility of the methodology.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!