Rh(i)-catalyzed stereoselective desymmetrization of prochiral cyclohexadienones via highly exo-selective Huisgen-type [3 + 2] cycloaddition |
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| Authors: | Krishna Kumar Gollapelli Vaibhav B Patil Allam Vinaykumar Rambabu Chegondi |
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| Institution: | Department of Organic Synthesis and Process Chemistry, CSIR-Indian Institute of Chemical Technology (CSIR-IICT), Hyderabad 500007 India ; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002 India, |
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| Abstract: | A Rh(i)-catalyzed highly stereoselective desymmetrization of 2-alkynylbenzaldehyde-tethered cyclohexadienones triggered by intramolecular Huisgen-type 3 + 2] cycloaddition has been developed. This method enables convergent construction of complex epoxy-bridged polycyclic ring systems with five contiguous stereocenters with excellent exo-selectivity and broad substrate scope. The highly atom-economical process involves 6-endo-dig cyclization of carbonyl oxygen onto an activated alkyne resulting in a highly reactive metal–benzopyrylium intermediate, which readily undergoes intramolecular 3 + 2] annulation/hydration. Asymmetric induction is also achieved for the first time in Rh(i)-catalyzed 1,3-dipolar cycloaddition using an easily accessible chiral diene as the ligand.A Rh(i)-catalyzed highly stereoselective desymmetrization of 2-alkynylbenzaldehyde-tethered cyclohexadienones triggered by intramolecular Huisgen-type 3 + 2] cycloaddition has been developed. |
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