Strain relief of oxetanes offers a plethora of opportunities for the synthesis of chiral alcohols and ethers. In this context, enantioselective desymmetrization has been identified as a powerful tool to construct molecular complexity and this has led to the development of elegant strategies on the basis of transition metal, Lewis acid, and Brønsted acid catalysis. This review highlights recent examples that harness the inherent reactivity of prochiral oxetanes and offers an outlook on the immense possibilities for synthetic application.
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http://dx.doi.org/10.1002/chem.202004923 | DOI Listing |
Chem Commun (Camb)
April 2024
Department of Organic Synthesis and Process Chemistry, India.
Organocatalytic asymmetric desymmetrization of prochiral cyclohexane-1,3-diones has been demonstrated through the merging of iminium and enamine activation. The tandem annulation reaction proceeds through a sequential oxa-Michael addition/intramolecular aldol reaction/[1,3]-amino oxetane rearrangement pathway. Mechanistic study using an O-water experiment suggests oxetane rearrangement instead of direct dehydration.
View Article and Find Full Text PDFIdentification of an electron poor trifluoroacetophenone allows the formation of uniquely stable hemiketals from prochiral oxetanols. When exposed to a cobalt(ii) catalyst, efficient ring-opening to densely functionalized dioxolanes is observed. Mechanistic studies suggest an unprecedented redox process between the cobalt(ii) catalyst and the hemiketal that initiates the oxetane-opening.
View Article and Find Full Text PDFOrg Lett
December 2021
Department of Organic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 43 Prague, Czech Republic.
Herein, we describe a versatile transition metal/oxidant free synthesis of the chiral 2-1,4-benzoxazines through chiral phosphoric acid (CPA) catalyzed enantioselective desymmetrization of prochiral oxetanes (30 examples) in up to 99% yield and 99% enantioselectivity under mild reaction conditions. The reported strategy not only complements the conventional 2-1,4-benzoxazine synthetic strategies but also provides access to key intermediates of therapeutic candidates, i.e.
View Article and Find Full Text PDFChemistry
April 2021
Department Chemie, Johannes Gutenberg Universität Mainz, Duesbergweg 10-14, 55128, Mainz, Germany.
Strain relief of oxetanes offers a plethora of opportunities for the synthesis of chiral alcohols and ethers. In this context, enantioselective desymmetrization has been identified as a powerful tool to construct molecular complexity and this has led to the development of elegant strategies on the basis of transition metal, Lewis acid, and Brønsted acid catalysis. This review highlights recent examples that harness the inherent reactivity of prochiral oxetanes and offers an outlook on the immense possibilities for synthetic application.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!