Synthesis of polysubstituted bicyclobutanes Rahul Suresh, Noam Orbach, Prof. Ilan Marek Technion-Israel Institute of Technology, Israel
Bicyclo[1.1.0]butane (BCB), the smallest fused ring carbocycle has fascinated chemists because of the unusual bonding 1 and reactivity. The “strain release” of BCBs has been used to access intricate molecular frameworks 2,3 and label peptides 4 . The central C-C bond of BCBs behaves like a pseudo-double bond reacting with nucleophiles, 2,5 electrophiles, 6-8 radicals 9 and carbenes. 7 However, these functionalizations were limited by the availability of polysubstituted BCBs. The available ones are either electronically biased or with few substituents. 2,5,7,9 (Bromomethyl)-iodocyclopropanes undergoes lithium-iodine exchange to generate the lithiated cyclopropanes which undergoes an intramolecular S N 2 reaction to furnish diastereo- and enantioenriched polysubstituted BCBs. 10 The former can be accessed easily from carbometallation reactions of cyclopropenes. 11 This methodology will allow easy, reliable, and efficient route for the synthesis of diastereo- and enantioenriched polysubstituted BCBs. References 1. Pomerantz, E. W. Abrahamson, J. Am. Chem. Soc . 1996 , 88 , 3970. 2. Panish, S. R. Chintala, D. T. Boruta, Y. Fang, M. T. Taylor, J. M. Fox, J. Am. Chem. Soc . 2013 , 135 , 9283. 3. Fawcett, T. Biberger, V. K. Aggarwal, Nat. Chem . 2019 , 11 , 117. 4. S. Baran et al. J. Am. Chem. Soc . 2017 , 139 , 3209. 5. Gaoni, A. TomažIč, J. Org. Chem. 1985 , 50 , 2948. 6. Von, J. F. Coburn, Tetrahedron Lett . 1965 , 6 , 991. 7. E. McNamee, A. L. Thompson, E. A. Anderson, J. Am. Chem. Soc. 2021 , 143 , 21246. 8. E. McNamee, N. Frank, K. Christensen, F. Duarte, E. A. Anderson, 9. Taming non-classical carbocations to control small ring reactivity, ChemRxiv, 2023 , doi:10.26434/chemrxiv-2023-zgdq8. B. Wiberg and R. P. Ciula, J. Am. Chem. Soc., 1959, 81, 5261. 10. I. D’yachenko, S. V Zotova, O. V Bragin, N. M. Abramova, A. Nesmeyanova, N. D. Zelinskii, Izv. Akad. Nauk. 1985 , 2043. 11. Cohen, I. Marek, Acc. Chem. Res. 2022 , 55 , 2848.
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