21622-07-1

Basic information

• Product Name: 1-Cyclopentene-1-acetic acid, methyl ester
• Synonyms: methyl 2-cyclopentenylacetate;1-cyclopentenylacetic acid methyl ester;methyl cyclopentenylacetate;methyl 1-cyclopenteneacetate
• CAS NO: 21622-07-1
• Molecular Formula: C8H12O2
• Molecular Weight: 140.182
• Mol File: 21622-07-1.mol
• Article Data: 3

Chemical Properties

• CAS DataBase Reference: 1-Cyclopentene-1-acetic acid, methyl ester(CAS DataBase Reference)
• NIST Chemistry Reference: 1-Cyclopentene-1-acetic acid, methyl ester(21622-07-1)
• EPA Substance Registry System: 1-Cyclopentene-1-acetic acid, methyl ester(21622-07-1)

Safety Data

• Hazardous Substances Data: 21622-07-1(Hazardous Substances Data)

Upstream product

• 67-56-1 methanol 
• 3968-30-7 5-cyclopentylidene-2,2-dimethyl-1,3-dioxane-4,6-dione 
• 22734-04-9 cyclopent-1-enyl-acetonitrile 
• 5927-18-4 trimethyl phosphonoacetate 
• 120-92-3 cyclopentanone 
• 96913-86-9 methyl cyclopentylidene malonate 
• 2426-02-0 3,4,5,6-Tetrahydrophthalic anhydride 
• 96913-91-6 cyclopentenylketene 

Downstream Products

• 40203-73-4 Cyclopentylideneacetic acid methyl ester 
• 74126-52-6 1-Hydroxycyclopentylacetic acid methyl ester 
• 30334-98-6 trans-2-phenylcyclopentaneacetic acid 
• 3974-41-2 cis-3-Phenylcyclopentylacetic acid 
• 30334-98-6 cis-2-phenylcyclopentaneacetic acid 
• 620-23-5 m-tolyl aldehyde 
• 5745-61-9 hexahydro-cyclopenta[b]furan-2-one 

Relevant articles and documents

Photocycloaddition of 3-alkenyloxy-2-cycloalkenones: Enantioselective lewis acid catalysis and ring expansion

By application of substoichiometric amounts (50 mol %) of a chiral Lewis acid, the intramolecular [2+2] photocycloaddition of the title compounds was achieved with high enantioselectivity (up to 94 % ee). Upon cleavage of the cyclobutane ring the resulting tricyclic products underwent ring-expansion reactions under acidic conditions and formed anellated seven- or eight-membered-ring systems without racemization. The ring expansion could be combined with a diastereoselective reduction (triethylsilane) or allylation (allyltrimethylsilane) upon BF3 catalysis (48-87 % yield). Ring-a-ring o'roses: An enantioselective, Lewis acid catalyzed [2+2] photocycloaddition (9 examples, 69-94 % yield, up to 94 % ee) leads to tricyclic products, in which the marked bond of the cyclobutane ring can be cleaved to form medium-sized rings as shown in the example above.

Mechanism of Fragmentation of Alkylidene-Meldrum's Acids. Carboxyketene, Vinylketene, and Methyleneketene Intermediates from 5-Cyclopentylidene-2,2-dimethyl-1,3-dioxane-4,6-dione

Three ketenes were successively observed on flash vacuum pyrolysis of 5-cyclopentylidene-2,2-dimethyl-1,3-dioxane-4,6-dione (5), viz., carboxycyclopentenylketene (11, 2126 cm-1), cyclopentylideneketene (12, 2087 cm-1), and cyclopentenylketene (13, 2110 cm-1). 11 was thermally converted to 13 and probably also to 12. 12 itself rearranged thermally to 13.The three ketenes were trapped with methanol to give the esters 14, 15, and 16. 14 was thermally unstable, rearranging at room temperature to methyl cyclopentylidenemalonate (14a) and decarboxylating at 150 deg C, predominantly to 16.A dimer of 12, 2,4-bis(cyclopentylidene)cyclobutane-1,3-dione (17), was also isolated. 1-Cyclopentenyldiazomethane (18) was prepared and pyrolyzed to 1,3-cyclohexadiene and benzene.No evidence for the formation of cyclohexyne (17) was obtained in any of these experiments.