Bismuth(III) Chloride‐Catalyzed Highly Efficient Transesterification of β‐Keto Esters

Abstract

Bismuth(III) chloride was found to be an efficient catalyst for the transesterification of a variety of β‐keto esters with a wide range of alcohols to afford transesterified products in good to high yields in short reaction times (see Table).

Recent advances in the transesterification of β-keto esters

“…93,94 The bismuth chloride-catalysed transesterification of a range of methyl and ethyl β-keto esters proceeded smoothly with aliphatic (entries 1 and 3), allylic (entries 7 and 12), propargyl (entry 6) and aromatic (entries 2, 4, 5, 8, 10 and 11) alcohols in good to excellent yields ( Table 39 ). 95 Comparable yields were recorded regardless of the nature of the substituents on the β-keto ester substrates.…”

Studies of the Electronic Effects of Zinc Cluster Catalysts and Their Application to the Transesterification of β‐Keto Esters

“…[1] In addition, unlike simple esters, the chelation nature of b-keto esters suppresses the activity of metal catalysts through the formation of ac oordinate bond to metal ions, and the acidic nature of b-keto esters (pK a % 14 in DMSO) suppresses the activity of the base catalyst. To date, several acidic and basic catalysts, such as DMAP, [17,28] zeolites, [29] super acid, [30] montmorillonite, [31] Zn/I 2 , [15a] amberlyst-15, [32] Nb 2 O 5 , [33] N-bromosuccinimide (NBS), [34] Al(H 2 PO 4 ) 3 , [35] and BiCl 3 , [36] have been used for the transesterification of b-keto esters. The substrate generality of b-keto esters, however,h as much room for improvement.A lmost all of the substrates used for the reactions were a-unsubstituted simple b-keto esters, and reactions of sterically more congested a-substituted b-keto esters have not been well studied.…”

AgOTf‐catalyzed transesterification of β‐keto esters

“…Again, NaBH 4 is a common reducing reagent and alcoholic solutions of sodium borohydride are neither strongly acidic nor basic, which makes it suitable for transesterification of acid‐ and base‐labile esters . Several Lewis acid catalysts such as BF 3 .OEt 2 , BiCl 3 and Bi(NO 3 ) 5 have also been reported for the transesterification of β ‐keto esters with alcohol.…”