73448-25-6

Upstream product

• 75-91-2 tert.-butylhydroperoxide 
• 542-92-7 cyclopenta-1,3-diene 
• 73448-15-4 4-tert-butoxycyclopent-2-en-1-one 
• 98-00-0 (2-furyl)methyl alcohol 
• 59995-47-0 4-Hydroxycyclopent-2-enone 
• 91966-26-6 cis- and trans-4-tert-butoxy-2-cyclopenten-1-yl acetate 

Downstream Products

• 930-30-3 cyclopent-2-enone 
• 75-65-0 tert-butyl alcohol 
• 25594-22-3 cis-3-t-butoxy-5-hydroxycyclopentene 
• 26054-46-6 cis-(±)-2-oxabicyclo[3.3.0]oct-6-en-3-one 

Relevant academic research and scientific papers

Nitrile oxide cycloaddition to 4-hydroxy-2-cyclopentenone: Solvent effect and selectivity

The facial selectivity in the nitrile oxide cycloaddition reactions of 4-hydroxy-2-cyclopentenone and its bulky t-butyloxy derivative is reported. A quantitative evaluation of the solvent effect on the hydrogen bonding directing ability is given, showing

Contra-steric Diels-Alder route to 3-oxodicyclopentadiene and meso 3,5-endo-dihydroxy-4,5-dihydrodicyclopentadiene

Diels-Alder reaction between cyclopentadiene and 4-tert-butoxycyclopentenone occurs in a contra-steric manner to give more hindered endo-3-tert-butoxydicyclopentadiene as the major product (~ 15:1) in excellent yield. The product has been transformed into either (±)- and (-)-3-oxodicyclopentadiene or meso 3,5-endo-dihydroxy-4,5-dihydrodicyclopentadiene efficiently.

The preparation of optically active 2-cyclopenten-1,4-diol derivatives from furfuryl alcohol

The preparation and enzymatic resolution of several cis-mono-4-O-protected-2-cyclopenten-1,4-diols are described. The process starts with inexpensive furfuryl alcohol and lends itself to the preparation of multigram quantities of various protected, optically active 2-cyclopenten-1,4-diol derivatives. Stereoselective reduction of 4-O-protected-2-cyclopentenone to the cis-mono-O-protected-2-cyclopenten-1,4-diol using LiAlH4/LiI or Red-Al/NaI is described. Subsequent pancreatin-promoted, stereoselective acylation was conducted on these cis-(+/-)-mono-O-protected-cyclopenten-1,4-diols to afford the corresponding alcohols and acetates in moderate to excellent enantioselectivities.

A new chiral route to optically pure 3-oxodicyclopentadiene: A versatile chiral cyclopentadienone synthon, via contra-steric Diels-Alder reaction

Optically pure oxodicyclopentadiene (KDP) has been prepared in both enantiomeric forms from racemic 4-tert-butoxycyclopent-2-en-1-one in three ways starting from 4-tert-butoxycyclopent-2-en-1-one involving contra-steric Diels-Alder reaction and lipase-mediated enantiospecific kinetic transesterification as key steps.

Photochemical Cycloadditions. III. Addition of 4-Substituted 2-Cyclopentenones to Allene; Configuration Determination by Lanthanide-Induced Shift Studies

Photoaddition of 4-substituted 2-cyclopentenones to 1,2-propadiene gave mixtures of the head-to-head and head-to-tail cycloadducts in a ratio of ca. 90:10.The stereoisomeric composition was sensitive to solvent changes, as was the chemical yield of the cycloadducts.Under otherwise identical conditions the highest yields were obtained in non-polar solvents.The configurations of the cycloadducts were determined by LIS and 13C NMR studies.

Stereochemical and Mechanistic Aspects of the Aprotic Conjugate Addition Reactions of the Carbanions of Octenyl Sulfides and Octenyl Thiocarbamates with 4-t-Butoxycyclopent-2-enone in the Presence of Hexamethylphosphoric Triamide

The carbanions of (E)- and (Z)-1-(phenylthio)oct-2-ene, (E)-1-(methylthio)- and 1-(t-butylthio)oct-2-ene, N,N-dimethyl S-thiocarbamate and (E)-oct-2-enyl benzothiazole undergo conjugate addition to 4-t-butoxycyclopent-2-enone in the presence of hexamethylphosphoric triamide (hmpa) in tetrahydrofuran at - 70 deg to give as predominant products diastereomeric mixtures of syn and anti allylic sulfides arising from reaction through C 1 of the octenyl carbanions.Also formed in some cases are small amounts of diastereomeric mixtures of syn and anti vinylic sulfides arising from reaction through C 3 of the octenyl carbanions.In the absence of the hmpa, carbonyl addition is the major reaction pathway of the carbanions of each of the (E)- and (Z)-octenyl thiocarbamates.The constitutions and stereostructures of all the products have been established through chemical shift and coupling constant correlations of their 1H n.m.r. data obtained at 400 MHz.The relative proportions of the regioisomeric allylic and vinylic sulfides are dependent both upon the nature of the non-allylic substituent attached to the sulfur atom, and the geometry of the double bond in the starting octenyl sulfide.While there is no apparent connection between the electronic properties or sizes of the non-allylic substituent and the diastereomer ratios of the allylic and vinylic sulfides, it is noted that the (Z)-(phenylthio)octene delivers an allylic sulfide mixture enriched in the syn isomer.It is concluded that the carbanions are configurationally stable at - 70 deg and that the configurations of the vinylic sulfides reflect the configurations of the carbanions from which they are derived.It is also concluded that the reactions proceed under orbital control, as this best accounts for the formation of the vinylic sulfides and is in accord with the results of STO-3G calculations carried out on a series of sulfur-bearing allylic carbanions.The likely angle of attack of the carbanions on the enone system is briefly discussed in terms of a published model relating to the attack of a simple nucleophile on an electrophilic double bond.

A Convenient Synthesis of 2-Cyclopentenone

A convenient and practical synthesis of 2-cyclopentenone has been developed.Keywords - 2-cyclopentenone; 4-tert-butoxy-2-cyclopentenol; 4-cumyloxy-2-cyclopentenol; dehydration

AN EFFICIENT SYNTHESIS OF cis-OXABICYCLOOCT-6-EN-3-ONE

An efficient synthesis of a prostaglandin synthon (+/-)-cis-oxabicyclooct-6-en-3-one (1) has been developed using cyclopentadiene (2) as starting material.Employing the same methodology optically active (1) is also synthesized in low optical purity.