5459-45-0

Upstream product

• 5394-63-8 2,2,6-trimethyl-4H-1,3-dioxin-4-one 
• 513-42-8 3-hydroxy-2-methyl-1-propene 
• 141-97-9 ethyl acetoacetate 
• 132426-20-1 2-methyl-prop-2-ene-1-yl bromoacetate 
• 674-82-8 4-methyleneoxetan-2-one 

Downstream Products

• 3240-09-3 5-methyl-5-hexen-2-one 
• 118662-99-0 3-(2-methyl-2-propenyl) 5-allyl 2,6-dimethyl-4-(3-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylate 

Relevant academic research and scientific papers

Ag-Cu nanoparticles as efficient catalysts for transesterification of β-keto esters under acid/base-free conditions

Transesterification of β-keto esters and alcohols are traditionally catalyzed by acid or basic catalysts. However, these traditional catalysts do not always meet the requirements of modern synthetic chemistry which need to be highly efficient, selective, and environmentally friendly. In this work, Ag-Cu metal sites were first introduced as transesterification catalysts. The effect of the support, Ag:Cu molar ratio, and reaction conditions were investigated. The Ag-Cu metal sites were proved to be active in the β-ketoester transesterification with various alcohols, having yields comparable to the conventional acid- or base-catalysts.

General and efficient transesterification of β-keto esters with various alcohols using Et3N as a br?nsted base additive

Transesterification of β-keto esters with a wide variety of allyl, benzyl, propargyl, and alkyl alcohols using, for the first time, commercially available and inexpensive Et3N as a Br?nsted base additive, is efficiently performed in toluene at reflux. The corresponding esters are exclusively obtained in 57-98% yields with no trace amounts of γ,δ-ketones, usually expected from the decarboxylative Carroll rearrangement.

α-EWG-substituted enones: Suitable substrates for ring-closing metathesis

The A-ring of hexacyclinic acid has been synthesised, using a ring-closing metathesis involving an α-EWG-substituted enone as the key step. We have then explored the scope of this reaction, which gives access to various 5- and 6-membered rings. Georg Thieme Verlag Stuttgart.

Enantioselective intramolecular cyclopropanations of allylic and homoallylic diazoacetates and diazoacetamides using chiral dirhodium(II) carboxamide catalysts

Diazo decomposition of allylic and homoallylic diazoacetates 10a-p and 22a-j catalyzed by chiral dirhodium(II) tetrakis[methyl 2-pyrrolidone-5(S)-carboxylate], Rh2(SS-MEPY)4 (7), and its enantiomer, Rh2(5R-MEPY)4 (8), produces the corresponding intramolecular cyclopropanation products 11a-p and 23a-j in good to excellent yields and with exceptional enantioselectivity. Higher enantiocontrol is observed with allylic diazoacetates than with their homoallylic counterparts, but allylic diazoacetates are subject to greater variations in enantioselectivities with changes in substitution patterns on the carbon-carbon double bond. For example, the enantioselectivities in the intramolecular cyclopropanations of 3-alkyl/aryl-2(Z)-alken-1-yl diazoacetates are generally ≥94%, whereas the cyclizations of the homologous 4-alkyl/aryl-3(Z)-alken-1-yl diazoacetates are typically in the range of 70-90% ee. The corresponding 3-alkyl/aryl-2(E)-alken-1-yl and 4-alkyl/aryl-3(E)-alken-1-yl diazoacetates undergo cyclization with slightly lower ee's (54-85%). Although the Rh2(5S-MEPY)4-catalyzed cyclization of the 2-methallyl diazoacetate 10c proceeds with only 7% ee, alternative chiral dirhodium(II) catalysts, including those with methyl N-acylimidazolidin-2-one-4(5)-carboxylate ligands such as Rh2(4S-MACIM)4 (14) and Rh2(4S-MPAIM)4 (15), may be employed to increase the level of enantiocontrol to 78 and 65%, respectively. Some allylic diazoacetamides also undergo highly enantioselective cyclization to form cyclopropyl lactams as illustrated by the diazo decomposition of N-allyl diazoacetamide (19) in the presence of dirhodium(II) tetrakis[methyl 2-oxazolidinone-4(S)-carboxylate], Rh2(4S-MEOX)4, to give the 3-azabicyclo[3.1.0]hexan-2-one 20 in 98% ee. The absolute configuration and the level of enantiocontrol in these intramolecular cyclopropanations have been interpreted by a transition state model in which the important determinants are (i) the preferred conformation about the rhodium-carbon bond; (ii) the trajectory of approach of the double bond to the metallocarbene center; and (iii) the orientation of the double bond with respect to the chiral face of the catalyst.

Facile synthesis of β-ketoesters mediated by Sml2: Reformatsky reaction type selfcondensation

α-Bromoesters are converted to β-ketoesters by treatment with samarium diiodide via self condensation under the mild conditions. The reaction appears to be initiated via the formation of samariun diiodide ester enolate for the Reformatsky reation type.