The first catalytic enantioselective and diastereoselective synthesis of atropisomeric hydrazides was achieved using a sequential catalysis protocol. This strategy is based on a one-pot sequence of two organocatalytic cycles featuring the enamine amination of branched aldehydes followed by nitrogen alkylation under phase-transfer conditions. The resulting axially chiral hydrazides were obtained directly from commercially available reagents in high yields and with good stereocontrol. The permutation of organocatalysts allowed easy access to all stereoisomers, enabling a stereodivergent approach to enantioenriched atropisomeric hydrazides.
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http://dx.doi.org/10.1002/anie.202209895 | DOI Listing |
Chem Sci
August 2024
Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE), Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University (NPU) 127 West Youyi Road Xi'an 710072 China
An efficient and highly enantioconvergent and diastereoselective ternary catalysis in a one-pot process is reported, which represents an integrated strategy for the synthesis of atropisomeric hydrazides with defined vicinal central and axial chirality from readily available racemic α-amino-ynones, azodicarboxylates, and Morita-Baylis-Hillman (MBH) carbonates. This method utilizes -generated racemic pyrrolin-4-ones hydroamination of racemic α-amino-ynones by AuCl catalysis as a novel and versatile C1 synthon, which engage commercially available azodicarboxylates to generate amination products in high yields and uniformly excellent enantioselectivities under the catalysis of a chiral phosphoric acid. Following amination, -alkylation catalyzed by diastereoselective organocatalyst afforded axially chiral hydrazides with excellent diastereoselectivities (>98 : 2 dr).
View Article and Find Full Text PDFMolecules
November 2023
Department of Industrial Chemistry "Toso Montanari", Alma Mater Studiorum University of Bologna, Via P. Gobetti 85, 40129 Bologna, Italy.
Org Chem Front
August 2023
Departments of Industrial & Physical Pharmacy and Chemistry, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN 47907.
Covalently linked molecular cages can provide significant advantages (including, but not limited to enhanced thermal and chemical stability) over metal-linked coordination cages. Yet, while large coordination cages can now be created routinely, it is still challenging to create chemically robust, covalently linked molecular cages with large internal cavities. This fundamental challenge has made it difficult, for example, to introduce endohedral functional groups into covalent cages to enhance their practical utility (e.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
August 2023
Department of Industrial Chemistry "Toso Montanari", Alma Mater Studiorum-University of Bologna, Viale del Risorgimento 4, 40136, Bologna, Italy.
Axially chiral compounds have been always considered a laboratory curiosity with rare prospects of being applied in asymmetric synthesis. Things have changed very quickly in the last twenty years when it was understood the important role and the enormous impact that these compounds have in medicinal, biological and material chemistry. The asymmetric synthesis of atropisomers became a rapidly expanding field and recent reports on the development of N-N atropisomers strongly prove how this research field is a hot topic open to new challenges and frontiers of asymmetric synthesis.
View Article and Find Full Text PDFThe growing importance of axially chiral architectures in different scientific domains has unveiled shortcomings in terms of efficient synthetic access and skeletal variety. This account describes our strategies in answering these challenges within the organocatalytic context where the emergence of bifunctional catalysts such as chiral phosphoric acids (CPAs) has proven invaluable in controlling the sense of axial chirality. The wide occurrence of bi(hetero)aryl skeletons in privileged structures constitutes a strong motivation to devise more effective arylation methods.
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