General and Efficient Transesterification ofβ-Keto Esters with Various Alcohols Using Et₃N as a Brønsted Base Additive

Recent advances in the transesterification of β-keto esters

“…Further investigations by the same group encompassed a range of allyl ( Table 12 , entries 1–5), benzyl (entry 6), propargyl (entry 7), and alkyl (entries 8–12) alcohols. 30 The reactions reached completion within 3–27 hours, affording the target esters in good yields. Carroll decarboxylative rearrangement or C-allylation products were not observed.…”

Expedient approach for trans-esterification of β-keto esters under solvent free conditions using silica supported boric acid (SiO2–H3BO3) as a recyclable catalyst

“…25 ) and aryl boronic acid 26 for similar transformations are well documented. Organic bases like DMAP, 27 2,6-lutidine 28 and triethyl amine in toluene, 29 and polyaniline-hydrochloride, 30 N , N -diethylaminopropylated silica (NDEAP-SiO 2 ) 31 and hexamethylene-tetramine 32 were also successfully used for trans-esterification of β-keto esters. Cordova and Janda reported lipase-catalysed trans-esterification of β-keto esters using Candida antarctica lipase B (CALB).…”

General [4 + 1] Cyclization Approach To Access 2,2-Disubstituted Tetrahydrofurans Enabled by Electrophilic Bifunctional Peroxides

“…d KO t Bu as base and THF as solvent were used. simply exchanging the ethoxy group in achiral esters with the chiral alcohol, 16 generally provided the tetrahydrofuran products 14a−f with high yields and diastereoselectivities (7:1 to >20:1 dr). A range of electron-donating and -withdrawing substrates were well tolerated for this reaction.…”

“…On the basis of the above results, we next screened several types of well-known chiral auxiliaries and finally found that a (+)-camphor-derived and conformationally very rigid chiral alcohol could successfully induce the cyclizations with high stereoselectivities. As shown in Table , asymmetric reactions of 3a with chiral esters 13a – f , which were readily prepared by simply exchanging the ethoxy group in achiral esters with the chiral alcohol, generally provided the tetrahydrofuran products 14a–f with high yields and diastereoselectivities (7:1 to >20:1 dr). A range of electron-donating and -withdrawing substrates were well tolerated for this reaction.…”