Claisen Rearrangement of Aliphatic Allyl Vinyl Ethers from 1912 to 2012: 100 Years of Electrophilic Catalysis

Abstract

This review summarizes, from a personal perspective, the development of catalytic asymmetric Claisen rearrangements from 1912 to 2012. 1 Introduction 2 Gosteli-Claisen Rearrangement 3 Claisen Rearrangement Using Stable Enols: Kojic Acid and Diosphenols 4 The Early Years: Catalysis by Brønsted Acids 5 Lewis Acid Mediated Claisen Rearrangements: The Aluminum Age 6 Catalysis by Precious Metals 7 Catalysis by σ-Lewis Acids 8 Catalysis by Achiral Organocatalysts 9 Catalytic Asymmetric Claisen Rearrangements 10 Conclusion

Base-Mediated Claisen Rearrangement of CF3-Containing Bisallyl Ethers

“…The similar consequence was noticed for Sc(OTf) 3 (Entry 5), and like the cases of other triflates like Mg(OTf) 2 , Yb(OTf) 3 , Gd(OTf) 3 (not shown in Table 4 ) [ 17 ], the total amounts of fluorinated compounds obtained after the reaction were only in a range of 40% to 60% including 5a in less than 5% yield. However, interesting to note is the fact that weakly acidic but non-nucleophilic 1,1,1,3,3,3-hexafluoropropan-2-ol (HFIP) [ 18 ] promoted the desired transformation nicely to afford 5a in 66% yield after stirring for 3 days at room temperature (Entry 6).…”