We describe the direct synthesis of γ-fluoro enals from the corresponding silyl dienol ethers. This simple process operates under mild conditions and is compatible with a wide range of functionalities. The high γ regioselectivity of this protocol was rationalized by means of theoretical calculations.
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http://dx.doi.org/10.1002/chem.202303545 | DOI Listing |
JACS Au
November 2024
Department of Organic Chemistry, Indian Institute of Science, Bangalore560012, India.
Compared to the widely explored enol silanes, the applicability of their extended variants especially as bisvinylogous nucleophiles in enantioselective catalysis has been sparse. Herein, we describe the first enantioselective vinylogous and bisvinylogous allenylic substitution using silyl dienol and trienol ethers, respectively, as a nucleophile. With racemic allenylic alcohols as the electrophile, these enantioconvergent reactions are cooperatively catalyzed by an Ir(I)/(phosphoramidite,olefin) complex and Lewis acidic La(OTf) and display remarkable regio- and diastereoselectivity in most cases.
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November 2024
Université Paris-Saclay, UVSQ, CNRS, UMR 8180, Institut Lavoisier de Versailles, 45 avenue des Etats-Unis, 78000, Versailles, France.
We report a general remote tribromo- and trichloromethylation process using CBr and CBrCl as ready available sources of trihalomethyl radicals. This method operates under mild and metal-free photocatalyzed conditions and enables the access to γ-trihalomethylated enals with complete regioselectivity in up to 71 % isolated yield. Importantly, this protocol is easily adapted to the selective one-pot synthesis of the corresponding γ-dihalomethylidenated enals in up to 49 % overall yield.
View Article and Find Full Text PDFNat Commun
July 2024
Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, School of Science and Research Center for Industries of the Future, Westlake University, Hangzhou, China.
Saturated three-dimensional carbocycles have gained increasing prominence in synthetic and medicinal chemistry. In particular, bicyclo[2.1.
View Article and Find Full Text PDFChem Sci
July 2024
Laboratory of Catalysis and Organic Synthesis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne 1015 Lausanne Switzerland
Bicyclic carbocycles containing a high fraction of Csp have become highly attractive synthetic targets because of the multiple applications they have found in medicinal chemistry. The formal cycloaddition of bicyclobutanes (BCBs) with two- or three-atom partners has recently been extensively explored for the construction of bicyclohexanes and bicycloheptanes, but applications to the synthesis of medium-sized bridged carbocycles remained more limited. We report herein the formal [4+2] cycloaddition of BCB ketones with silyl dienol ethers.
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August 2024
School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo, 192-0392, Japan (HY) (TM.
Herein we report that readily available 4-alkenylisocoumarins can be regarded as potent dienolate equivalents. For example, lactol silyl ethers derived from 4-alkenylisocoumarins were selectively converted to the corresponding benzo-homophthalates through a fluoride-induced ring opening step that was followed by a ring closure through a vinylogous intramolecular aldol condensation. Likewise, nucleophilic activation of 4-alkenylisocoumarins directly yields diversely poly-substituted naphthalenes and anthracenes without formation of any regioisomer.
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