63393-57-7

Upstream product

• 2612-29-5 2-ethyl-1,3-propandiol 
• 161449-31-6 1,3-di-O-acetyl-2-ethyl-1,3-propanediol 
• 18795-92-1 1,1-dimethyl 2-ethylcyclopropane-1,1-dicarboxylate 
• 88950-66-7 (1RS,2SR)-1-[(tert-butoxycarbonyl)amino]-2-ethylcyclopropane-1-carboxylic acid 
• 161449-58-7 (1S,2S)-1-(N-diphenylmethyleneamino)-2-ethylcyclopropanecarbonitrile 
• 97935-34-7 Potassium; (1R,2S)-2-ethyl-1-methoxycarbonyl-cyclopropanecarboxylate 
• 97935-31-4 2-ethylcyclopropane-1,1-dicarboxylic acid di-tert-butyl ester 
• 138457-95-1 (1S,2S)-1-Amino-2-ethyl-cyclopropanecarboxylic acid methyl ester 
• 134639-29-5 C₁₆H₂₃NO₂ 
• 87429-74-1 3-Azido-4-ethyl-4,5-dihydro-3H-pyrazole-3-carboxylic acid methyl ester 
• 81852-62-2 Methyl (Z)-2-azido-pentenoate 

Downstream Products

• 98244-40-7 (1S,2R)-1-((S)-2-Ethoxycarbonyloxy-2-phenyl-acetylamino)-2-ethyl-cyclopropanecarboxylic acid methyl ester 
• 98244-44-1 (1S,2R)-1-((R)-2-Ethoxycarbonyloxy-2-phenyl-acetylamino)-2-ethyl-cyclopropanecarboxylic acid methyl ester 
• 98189-21-0 (1R,2S)-1-((S)-2-Ethoxycarbonyloxy-2-phenyl-acetylamino)-2-ethyl-cyclopropanecarboxylic acid methyl ester 
• 65878-52-6 (+)-(1S,2R)-allocoronamic acid 
• 65878-53-7 (+)-(1R,2S)-allocoronamic acid 
• 106-98-9 1-butylene 

Relevant academic research and scientific papers

Titanium-mediated diastereoselective formation of (E)- or (Z)-2-substituted 1-vinylcyclopropanols: Scope and limitation, applications

Titanium-mediated cyclopropanation of α,β-unsaturated esters failed to provide 1-vinylcyclopropanol derivatives in useful yields, but (E)-2-substituted-1-vinylcyclopropanols were formed diastereoselectively from O-protected β-oxo- and β-halo esters, with the allylic double bond being created subsequently (Knoevenagel condensation or dehydrohalogenation). Titanium-mediated cyclopropanation of homoallyl alk-2-enoates, on the other hand, directly provided the corresponding Z diastereomers. Palladium(0)-catalysed azidation of their sulfonic esters (tosylate, mesylate), azide reduction, and subsequent double bond cleavage afforded (E)- or (Z)-2-alkyl-2,3-methanoamino acids, although improvements are required to perform the total asymmetric syntheses of molecules with three membered-rings by these methods. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.

A convenient approach to substituted 1-(1-alkenyl)cyclopropanols: A new preparation of 2,3-methanoamino acids

The diastereoselective titanium(IV)-mediated cyclopropanation of ethyl 3,3-diethoxypropionate by Grignard reagents, followed by modified Knoevenagel condensation with malonic acid under microwave irradiation, allow the preparation of (E)-1-(1-alkenyl)cyclopropanol derivatives, suitable precursors of πn-1,1-dimethyleneallylmetal species. The azidation of such complexes, followed by a reduction-oxidation sequence led to pure (E)-2,3-methanoamino acids. (C) 2000 Elsevier Science Ltd.

Stereoselective synthesis of highly functionalized cyclopropanes. Application to the asymmetric synthesis of (1S,2S)-2,3-methanoamino acids

One-pot palladium(0)-catalyzed alkylation and S(N') cyclization of 1,4- dichlorobut-2-ene 1 by the anion of α-substituted carbonitriles 2a-d can provide highly functionalized cyclopropanes (E)-4a-d, diastereoselectivity, (de 88-100%). Several attempts to achieve the asymmetric synthesis of the 1- amino-2-ethenylcyclopropanecarbonitrile (E)-9, by means of this new procedure, i.e., using chiral palladium ligands, chiral aminoacetonitriles (- )- and (+)-12 (from 1-hydroxypinanone) or chiral allyl chlorides (4S)-20b-d and (4R)-20e (from (2S) ethyl lactate) have pointed up the reversibility of the palladium-catalyzed cyclization step, responsible for the low enantioselectivity observed (ee ≤ 32%) and for the formation of byproducts, i.e., azepine derivatives 8a,b arising from subsequent aza Cope ring expansion. Molecular mechanics calculations using a modified MM2 type force field adapted to the π-allyl palladium complexes have explained these results. However, When performed under the Mitsunobu reaction conditions (DEAD, PMe3), therefore, in the absence of palladium catalyst, the S(N'), cyclization occurred also diastereoselectively (de > 88%) and provided the enantiomerically enriched 1-amino-2-propenylcyclopropanecarbonitrile (E)-22 (ee > 83%) suitable precursor of (1S,2S)-2,3-methanoamino acids.

Palladium (O) catalyzed tandem alkylation and SN′ cyclization of 1,4-dichlorobut-2-ene by the N-(diphenylmethylene)acetonitrile. a stereoselective synthesis of 1-aminocyclopropanecarboxylic acids

Racemic coronamic acid has been prepared with 100% diastereoselectivity from one pot palladium (O) catalyzed alkylation and SN′ cyclization of 1,4-dichlorobut-2-ene by the benzophenone Schiff base of aminoacetonitrile.

Practical Stereoselective Syntheses of All Four Stereoisomers of Coronamic Acid (2-Ethyl-1-aminocyclopropane-1-carboxylic acid)

All four stereoisomers of coronamic acid were synthesized from both enantiomers of 1,2-butanediol.Cyclopropanation of cyclic sulfate with the dibenzyl malonate anion gave cyclopropane dibenbzyl ester in a quantitative yield.Transformation into a protected amino acid was acieved by stereoselective hydrolysis and Curtius rearrangement as the key step.Saponification and subsequent acidic hydrolysis in one pot and ion exchange gave a free amino acid in a high yield.

Total asymmetric syntheses of (1S,2S)-norcoronamic acid, and of (1R,2R)- and (1S,2S)-coronamic acids from the diastereoselective cyclization of 2-(N-benzylideneamino)-4-chlorobutyronitriles

(3R)-2-(N-Benzylideneamino)-4-chloro-3-methylbutyronitrile 3, prepared from the commercially available methyl (2S)-3-hydroxy-2-methyl propionate 5 (96percent ee), readily underwent potassium carbonate induced cyclization to provide, after acid hydrolysis (6 N HCl) and chromatography, the (1S,2S)-norcoronamic acid 1a with 88percent diastereoselectivity and above 95percent enantiomeric excess.From (2R)-2-(hydroxymethyl)butyl acetate 23 (above 88percent ee) obtained by enzymatic enantioselective hydrolysis with lipase PS, was prepared the (3S)-2-(N-benzylideneamino)-3-(chloromethyl)valeronitrile 29, which after base-induced cyclization (K2CO3) and acid (6 N HCl) or basic (0.8 N NaOH) hydrolysis led to the non-natural (1R,2R)-coronamic acid 18 (>88percent ee).Also from this same acetate (2R)-23 was prepared the (3R)-3-(chloromethyl)-2-pentanenitrile 37, which provided the (1S,2S)-coronamic acid 17 (above 88percent ee) after base-induced cyclization (K2CO3 or LDA) and acid hydrolysis (6 N HCl).It is noteworthy that these short synthetic sequences, which do not require any expensive chiral auxiliary or optically active precursors, do not alter the enantiomeric purity of the stereogenic centers of these 2,3-methanoamino acids.However, the E diastereoselctivity of these cyclizations was not improved by using bulky N-(diphenylmethylene)amino substituent, contrary to results of some molecular mechanic calculations (MAD).

ASYMMETRIC SYNTHESIS OF CIS AND TRANS 2-METHYL AND 2-ETHYL 1-AMINO CYCLOPROPANECARBOXYLIC ACIDS

A new four step asymmetric synthesis of 2-methyl and 2-ethyl 1-amino cyclopropane carboxylic acids resulted from the cycloaddition of diazomethane to the corresponding chirally derivatized dehydro-aminoacid.

A CONVENIENT SYNTHESIS OF REGIO-SPECIFICALLY 2-ALKYLATED-3-DEUTERIATED-1-AMINOCYCLOPROPANE-1-CARBOXYLIC ACIDS

A simple procedure for the large scale preparations of regio-specifically 2-alkylated-3-deuteriated-1-aminocyclopropane-1-carboxylic acids from 1-deuterio-1,2-dibromoalkanes is described.