LaszlO Kurti

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Name: ?Kurti, Laszlo; László Kürti

Organization: Rice University , USA

Department: Department of Chemistry

Title: Associate(PhD)

TOPICS

Organic Chemistry

Organocatalysis

Chemicals
References

Practical Singly and Doubly Electrophilic Aminating Agents: A New, More Sustainable Platform for Carbon–Nitrogen Bond Formation

Co-reporter:Padmanabha V. Kattamuri, Jun Yin, Surached Siriwongsup, Doo-Hyun Kwon, Daniel H. Ess, Qun Li, Guigen Li, Muhammed Yousufuddin, Paul F. Richardson, Scott C. Sutton, and László Kürti

Journal of the American Chemical Society August 16, 2017 Volume 139(Issue 32) pp:11184-11184

Publication Date(Web):June 26, 2017

DOI:10.1021/jacs.7b05279

Given the importance of amines in a large number of biologically active natural products, active pharmaceutical ingredients, agrochemicals, and functional materials, the development of efficient C–N bond-forming methods with wide substrate scope continues to be at the frontier of research in synthetic organic chemistry. Here, we present a general and fundamentally new synthetic approach for the direct, transition-metal-free preparation of symmetrical and unsymmetrical diaryl-, arylalkyl-, and dialkylamines that relies on the facile single or double addition of readily available C-nucleophiles to the nitrogen atom of bench-stable electrophilic aminating agents. Practical single and double polarity reversal (i.e., umpolung) of the nitrogen atom is achieved using sterically and electronically tunable ketomalonate-derived imines and oximes. Overall, this novel approach represents an operationally simple, scalable, and environmentally friendly alternative to transition-metal-catalyzed C–N cross-coupling methods that are currently used to access structurally diverse secondary amines.

Direct and Stereospecific Synthesis of N-H and N-Alkyl Aziridines from Unactivated Olefins Using Hydroxylamine-O-Sulfonic Acids

Co-reporter:Dr. Zhiwei Ma;Dr. Zhe Zhou; Dr. László Kürti

Angewandte Chemie 2017 Volume 129(Issue 33) pp:10018-10022

Publication Date(Web):2017/08/07

DOI:10.1002/ange.201705530

AbstractA RhII-catalyzed direct and stereospecific N-H- and N-alkyl aziridination of olefins is reported that uses hydroxylamine-O-sulfonic acids as inexpensive, readily available, and nitro group-free aminating reagents. Unactivated olefins, featuring a wide range of functional groups, are converted into the corresponding N-H or N-alkyl aziridines in good to excellent yields. This operationally simple, scalable transformation proceeds efficiently at ambient temperature and is tolerant towards oxygen and trace moisture.

Direct and Stereospecific Synthesis of N-H and N-Alkyl Aziridines from Unactivated Olefins Using Hydroxylamine-O-Sulfonic Acids

Co-reporter:Dr. Zhiwei Ma;Dr. Zhe Zhou; Dr. László Kürti

Angewandte Chemie International Edition 2017 Volume 56(Issue 33) pp:9886-9890

Publication Date(Web):2017/08/07

DOI:10.1002/anie.201705530

Non-Deprotonative Primary and Secondary Amination of (Hetero)Arylmetals

Co-reporter:Zhe ZhouZhiwei Ma, Nicole Erin Behnke, Hongyin Gao, László Kürti

Journal of the American Chemical Society 2016 Volume 139(Issue 1) pp:115-118

Publication Date(Web):December 22, 2016

DOI:10.1021/jacs.6b12712

Herein we disclose a novel method for the facile transfer of primary (−NH2) and secondary amino groups (−NHR) to heteroaryl- as well as arylcuprates at low temperature without the need for precious metal catalysts, ligands, excess reagents, protecting and/or directing groups. This one-pot transformation allows unprecedented functional group tolerance and it is well-suited for the amination of electron-rich, electron-deficient as well as structurally complex (hetero)arylmetals. In some of the cases, only catalytic amounts of a copper(I) salt is required.

Symmetry in Cascade Chirality-Transfer Processes: A Catalytic Atroposelective Direct Arylation Approach to BINOL Derivatives

Co-reporter:Jin-Zheng Wang; Jin Zhou; Chang Xu; Hongbin Sun; László Kürti;Qing-Long Xu

Journal of the American Chemical Society 2016 Volume 138(Issue 16) pp:5202-5205

Publication Date(Web):April 7, 2016

DOI:10.1021/jacs.6b01458

Herein we disclose a scalable organocatalytic direct arylation approach for the regio- and atroposelective synthesis of non-C2-symmetric 2,2′-dihydroxy-1,1′-binaphthalenes (BINOLs). In the presence of catalytic amounts of axially chiral phosphoric acids, phenols and naphthols are coupled with iminoquinones via a cascade process that involves sequential aminal formation, sigmatropic rearrangement, and rearomatization to afford enantiomerically enriched BINOL derivatives in good to excellent yields. Our studies suggest that the (local) symmetry of the initially formed aminal intermediate has a dramatic impact on the level of enantioinduction in the final product. Aminals with a plane of symmetry give rise to BINOL derivatives with significantly lower enantiomeric excess than unsymmetrical ones featuring a stereogenic center. Presumably asymmetric induction in the sigmatropic rearrangement step is significantly more challenging than during aminal formation. Sigmatropic rearrangement of the enantiomerically enriched aminal and subsequent rearomatization transfers the central chirality into axial chirality with high fidelity.

Practical Organocatalytic Synthesis of Functionalized Non-C2-Symmetrical Atropisomeric Biaryls

Co-reporter:Dr. Hongyin Gao;Dr. Qing-Long Xu;Craig Keene;Dr. Muhammed Yousufuddin;Dr. Daniel H. Ess;Dr. László Kürti

Angewandte Chemie International Edition 2016 Volume 55( Issue 2) pp:566-571

Publication Date(Web):

DOI:10.1002/anie.201508419

Abstract

An organic acid catalyzed direct arylation of aromatic C(sp²)H bonds in phenols and naphthols for the preparation of 1,1′-linked functionalized biaryls was developed. The products are non-C₂-symmetrical, atropoisomeric, and represent previously untapped chemical space. Overall this transformation is operationally simple, does not require an external oxidant, is readily scaled up (up to 98 mmol), and the structurally diverse 2,2′-dihydroxy biaryl (i.e., BINOL-type), as well as 2-amino-2′-hydroxy products (i.e., NOBIN-type) are formed with complete regioselectivity. Density-functional calculations suggest that the quinone and imino-quinone monoacetal coupling partners are exclusively arylated at their α-position by an asynchronous [3,3]-sigmatropic rearrangement of a mixed acetal species which is formed in situ under the reaction conditions.

Practical Organocatalytic Synthesis of Functionalized Non-C2-Symmetrical Atropisomeric Biaryls

Co-reporter:Dr. Hongyin Gao;Dr. Qing-Long Xu;Craig Keene;Dr. Muhammed Yousufuddin;Dr. Daniel H. Ess;Dr. László Kürti

Angewandte Chemie 2016 Volume 128( Issue 2) pp:576-581

Publication Date(Web):

DOI:10.1002/ange.201508419