Reported herein is the efficient synthesis of tetra- and tri-substituted (Z)-fluoro- and (Z)-chloro-borylalkenes by the Boron-Wittig reaction of ketones and aldehydes with bench-top stable halo-diborylmethanes. The substrate scope is broad and the Boron-Wittig reaction proceeds from a diverse range of ketones and aldehydes including biologically relevant molecules with fluoro- or chloro-diborylmethanes, providing tetra- and tri-substituted (Z)-fluoro- and (Z)-chloro-borylalkenes in good yields with high stereoselectivity. The utilities of the obtained (Z)-fluoro- and (Z)-chloro-borylalkenes are highlighted by further modifications to afford fluoroalkene derivatives or all-carbon substituted alkene.
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http://dx.doi.org/10.1002/anie.202210532 | DOI Listing |
Nat Commun
November 2024
State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002, PR China.
Photocatalytic N-to-C aryl migration allows for quick construction of highly useful amide derivatives from readily available compounds. By developing the reactions of sodium sulfinates with the N-aryl-propiolamides, we herein demonstrate that the CO-promoted visible-light-induced method enables a large variety of aryl groups on nitrogen atoms of the N-arylamides to undergo efficient aryl migration from N atom to C atom to synthesize tetra- and tri-substituted alkenyl amides selectively. 1,4-N-to-C aryl migration is a key step in this transformation which is achieved through photocatalytic radical-polar crossover pathway.
View Article and Find Full Text PDFJ Org Chem
June 2024
Key Laboratory for Advanced Materials and Institute of Fine Chemicals, School of Chemistry & Molecular Engineering, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237, China.
Organocatalyzed diastereo- and enantioselective [3 + 2] cycloaddition reactions of donor-acceptor (D-A) cyclopropanes with isatin-derived ketimines are presented. Different from well-developed Lewis acid activation protocols which promote the reactivity of D-A cyclopropanes through coordinating to the acceptor group, in this reaction, dicyanocyclopropylmethyl ketones can be activated through nucleophilic activation of the donor group by using dihydroquinine-derived squaramide as Brønsted base catalyst. The reaction affords functionalized spiro[oxindole-3,2'-pyrrolidines] with two nonadjacent tetra- and tri-substituted stereocenters in 83-99% yields, moderate to excellent diastereoselectivities (up to >20:1 diastereomeric ratio (dr)), and excellent enantioselectivities (up to >99% enantiomeric excess (ee)) under mild conditions.
View Article and Find Full Text PDFNat Commun
October 2023
CAS Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Shanghai, 200032, China.
Transition metal-catalyzed asymmetric hydrofunctionalizations of unsaturated bonds via π-ƞ substitution have emerged as a reliable method to construct stereogenic centers, and mainly rely on the use of heteroatom-based or carbon nucleophiles bearing acidic C-H bonds. In comparison, sp carbon nucleophiles are generally not under consideration because of enormous challenges in cleaving corresponding inert sp C-H bonds. Here, we report a protocol to achieve asymmetric formal sp hydrocarbonations, including hydroalkenylation, hydroallenylation and hydroketenimination of both 1,3-dienes and alkynes via hydroalkylation and Wittig reaction cascade.
View Article and Find Full Text PDFInt J Biol Macromol
September 2023
Medicinal Chemistry Research Laboratory, School of Pharmaceutical Sciences, Siksha 'O' Anusandhan Deemed to be University, Bhubaneswar 751003, Odisha, India. Electronic address:
Our cascading attempt to develop new potent molecules now involves designing a series of imidazole derivatives and synthesizing two sets of 2,4,5- tri-substituted (4a-4d) and 1,2,4,5-tetra-substituted (6a-6d) imidazole by the principle of Debus-Radziszewski multicomponent synthesis reaction. The structures of the obtained compounds were confirmed by H/C NMR, FT-IR, elemental analysis, purity and the retention time was analyzed by HPLC. Based upon the binding affinity in the molecular docking studies, we have synthesized different imidazole derivatives from which compound 6c have been found to show more anti-proliferative activity by inducing apoptosis at a higher rate than the other compounds corroborating the in-silico prediction.
View Article and Find Full Text PDFJ Agric Food Chem
June 2023
Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566, Japan.
One novel tri-substituted tetrahydropyran type 8,7'-neolignan and its enantiomer with higher enantiomeric excess were synthesized from all -tetra-substituted tetrahydrofuran with an iodomethyl group by a hydride or H ring-expansion reaction. The normal hydride reductions of C-I bonds of tetra-substituted tetrahydrofurans bearing iodomethyl groups were observed in other 2,3-s-stereoisomers of tetra-substituted tetrahydrofurans to give tetra-substituted tetrahydrofurans bearing 7,8- and 8,7'-neolignan structures. The phytotoxicities of their synthesized compounds were compared with previously synthesized 7,8--8,7'-neolignans bearing tetra-substituted tetrahydrofurans to find out the highest phytotoxic tri-substituted tetrahydropyran type 8,7'-neolignan.
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