Asymmetric allylic alkylation of Morita-Baylis-Hillman fluorides with silyl enol ethers under Lewis-base catalysis Jordi Duran and Xavier Companyó, Javier Mateos, Lucija Ruzaj Universitat de Barcelona, Spain Keywords: Asymmetric Allylic Alkylation ▪ Allylic Defluorination ▪ MBH Fluorides ▪ Lewis-base Catalysis In the last few years, Morita-Baylis-Hillman (MBH) acetates and carbonates have been widely employed as substrate in Lewis-base catalysed asymmetric allylic alkylation (AAA). 1 Conversely, the use of MBH fluorides has received much less attention. The few reported methodologies are based on similar approach, where fluorine acts as a leaving group and activates a silicon pronucleophile. Specifically, these works tackle the fluoride-assisted Si-C and Si-N bond activation. 2 Herein is presented a novel asymmetric allylic alkylation between MBH fluorides and silyl enol ethers under Lewis-base catalysis relying on fluoride-assisted Si-O bond activation (Figure 1). 3 The products, bearing two contiguous stereocentres, are generated with excellent diastereo- and enantioselectivities. Mechanistic investigations suggest the formation of a complex between the two reaction partners via a Si-F interaction, which govern the diastereoselectivity of the process.
Figure 1.General approach of this work: AAA with MBH Fluorides via Si-O activation. References 1. Calcatelli, A.; Cherubini-Celli, A.; Carletti, E.; Companyó, X. Synthesis 2020 , 51 , 2922. 2. Nishimine, T.; Fukushi, K.; Shibata, N.; Taira, H.; Tokunaga, E.; Yamano, A.; Shiro, M.; Shibata, N. Angew. Chem. Int. Ed Engl. 2014 , 55 , 359. (b) Zi, Y.; Lange, M.; Schultz, C.; Vilotijevic, I. Angew. Chem. Int. Ed Engl. 2019 , 58 , 10727. 3. Duran, J.; Mateos, J.; Ruzaj, L.; Companyó, X. Manuscript in preparation.
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