Herein, we report a zirconium-catalyzed enantio- and diastereoselective inter/intramolecular double carboalumination of unactivated 2-substituted 1,5-dienes, which provides efficient and direct access to chiral cyclopentanes through the generation of two stereocenters, including one all-carbon quaternary stereocenter, generally with excellent diastereo- and high enantioselectivity. This tandem carboalumination process creates two new C-C bonds as well as one C-Al bond, which can be oxidized in situ with O or hydrolyzed. Furthermore, the obtained chiral cyclopentanes can be readily functionalized to provide various chiral compounds.
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http://dx.doi.org/10.1002/anie.201706198 | DOI Listing |
Phytochemistry
January 2025
College of Chemistry and Material Sciences, South-Central Minzu University, Wuhan, 430074, PR China. Electronic address:
Seven undescribed iridoids, identified as valeriridoids A-E (compounds 1, 5, 18, 19a, 19b, 20a, and 20b), were isolated from the roots and rhizomes of Valeriana officinalis L., along with sixteen known iridoids and nine known lignans. The structures were elucidated using NMR and MS spectroscopy, and the absolute configurations of the undescribed iridoids were determined through ECD calculations.
View Article and Find Full Text PDFJ Org Chem
November 2024
Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran 14115-175, Iran.
Herein, we present a green cascade approach for synthesizing a range of chemoselective polysubstituted pyrano[3',4':3,4]cyclopenta[1,2-]chromenes containing a chiral stereocenter. The strategy involves a metal-free nucleophilic reaction between dialkyl (2)-2-{2-oxo-3-[(2)-3-aryl-2-propenoyl]-2-chromen-4-yl}-2-butenedioates and α,α-dicyanoolefins under reflux conditions in ethanol solvent. Mechanistic studies have shown that the reaction proceeds via a cascade of steps, including Michael addition, intramolecular C- and -cyclization, intramolecular trans-esterification, [1,2]- and [1,5]-methoxy- and ethoxy carbonyl shift, and finally aromatization to yield the desired product.
View Article and Find Full Text PDFOrg Lett
October 2024
Department of Biochemistry, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390-9038, United States.
We report the stereoselective total synthesis of rhodocoranes I and J in 10 steps and 16.4% overall yield from ()-limonene. The synthesis was accomplished through the convergent assembly of a highly substituted chiral cyclopentanone and a lithiated furanyl silyl ketene acetal.
View Article and Find Full Text PDFInorg Chem
September 2024
Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland.
Optically pure ()- and racemic (/)--1,2-di(tetrazol-1-yl)cyclopentane were synthesized and used to prepare homo- and heterochiral Fe(II) coordination compounds. [Fe((/)-CHN)(CHCN)](BF) (), [Fe((/)-CHN)(CHCN)](BF) (), [Fe(()-CHN)(CHCN)](BF)·2CHCN (), and [Fe(()-CHN)(CHCN)](BF) () form a family of one-dimensional coordination polymers. Fe(II) cations in these complexes are characterized by a heteroleptic coordination environment: the neighboring metal centers are bridged by two 1,2-di(tetrazol-1-yl)cyclopentane molecules, while the nitrile molecules (acetonitrile or propionitrile, respectively) occupy the axial positions.
View Article and Find Full Text PDFOrg Biomol Chem
September 2024
Key Laboratory of Green Chemistry & Technology of Ministry of Education, College of Chemistry, Sichuan University, Chengdu 610064, PR China.
The first asymmetric synthesis of (-)-penostatins B and D and the practical synthesis of (+)-penostatins A and C have been accomplished through a flexible strategy. The features of the synthesis are a BF·OEt-mediated Diels-Alder reaction of chiral dienophiles and methylcyclopentadienes with high chemo-, regio-, and stereoselectivity, followed by ozonolysis to install the common trisubstituted cyclopentane intermediate, and a hetero-Diels-Alder reaction with easily tunable facial selectivity, followed by sulfonate elimination to construct both enantiomeric tricyclic systems for penostatins A/C and B/D, respectively.
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