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Cyclopentenone also functions as an excellent dienophile in the Diels–Alder reaction, reacting with a wide variety of dienes. In one example, a Danishefsky-type diene is reacted with a cyclopentenone to yield a fused tricyclic system en route to the synthesis of coriolin. [6] Cyclopentenone in the synthesis of coriolin
1,2-Cyclopentanedione is the organic compound with the formula (CH 2) 3 (CO) 2.It is one of two isomeric cyclopentanediones, the other being 1,3-cyclopentanedione.It was first prepared by base-induced condensation of di ethylglutarate with diethyloxalate, followed by hydrolysis of the resulting diketodiester followed by decarboxylation. [1]
Ketene cycloadditions proceed by a concerted, [2+2] cycloaddition mechanism. Ketenes, unlike most alkenes, can align antarafacially with respect to other alkenes. Thus, the suprafacial- antarafacial geometry required for concerted, thermal [2+2] cycloaddition can be achieved in reactions of ketenes. [4]
A bulky substituent at the C2 or C3 position can increase reaction rate by destabilizing the s-trans conformation and forcing the diene into the reactive s-cis conformation. 2-tert-butyl-buta-1,3-diene, for example, is 27 times more reactive than simple butadiene.
In this notation, a Diels-Alder reaction is a (4+2)cycloaddition and a 1,3-dipolar addition such as the first step in ozonolysis is a (3+2)cycloaddition. The IUPAC preferred notation however, with [i+j+...] takes electrons into account and not atoms. In this notation, the DA reaction and the dipolar reaction both become a [4+2]cycloaddition.
Dibenzylideneacetone is a well known dienone. A dienone is a class of organic compounds with the general formula (R 2 C=CR) 2 C=O, where R is any substituent, but often H.They are formally "derived from 1,4-diene compounds by conversion of a –CH2– group into –C(=O)– group", resulting in "a conjugated structure".
1,3-Cyclopentanedione is an organic compound with the formula (CH 2) 3 (CO) 2. It is one of two isomeric cyclopentanediones, the other being 1,2-cyclopentanedione. The enol is predicted to be about 1-3 kcal/mol more stable than the diketo form. [1] The enol structure has been confirmed by X-ray crystallography. [2]
Cyclopentenone prostaglandins are a subset of prostaglandins (PGs) or prostanoids (see Eicosanoid §§ Classic eicosanoids and Nonclassic eicosanoids) that has 15-deoxy-Δ12,14-prostaglandin J2 (15-d-Δ12,14-PGJ2), Δ12-PGJ2, and PGJ2 as its most prominent members but also including PGA2, PGA1, and, while not classified as such, other PGs. 15-d-Δ12,14-PGJ2, Δ12-PGJ2, and PGJ2 share a common ...