16189-35-8

Upstream product

• 825-25-2 2-cyclopentylidenecyclopentan-1-one 
• 91011-88-0 1,1'-Dibromo-1,1'-bicyclopentane 
• 51175-23-6 11-oxa-dispiro[4.0.4.2]dodecan-12-one 
• 1528-30-9 methylenecyclopentane 
• 5011-61-0 dispiro[4.1.4.1]dodecane-6,12-dione 
• 65261-04-3 1-nitro-1-(1-nitrocyclopentyl)cyclopentane 
• 120-92-3 cyclopentanone 
• 5181-75-9 bicyclopentyl-1,1'-diol 
• 34008-65-6 dicyclopentyl sulfone 
• 4524-93-0 Cyclopentanecarboxylic acid chloride 

Downstream Products

• 311-38-6 6,7,13,14-tetraoxadispiro[4.2.4⁸.2⁵]tetradecane 
• 120-92-3 cyclopentanone 
• 135084-70-7 1-(1-cyclopent-1-enylcyclopentyl)-4-phenyl-1,2-dihydro-1,2,4-triazole-3,5-dione 
• 129731-35-7 6,12,13-Trioxadispiro<4.1.4.2>tridecan 
• 13388-94-8 spiro[4.5]decan-6-one 

Relevant academic research and scientific papers

Ring strain release as a strategy to enable the singlet state photodecarbonylation of crystalline 1,4-cyclobutanediones

Challenging most chemists' intuition, highly reactive dialkyl biradicals can be reliably generated in the solid state by taking advantage of the photodecarbonylation of cyclic ketones. However, it has been shown that radical stabilizing groups with resonance-delocalizing abilities at the α-carbons of the precursor are required to facilitate the α-cleavage reaction, and that triplet state reactivity is essential to slow down the combination of the intermediate acyl-alkyl biradical back to the starting ketone. Relatively long triplet acyl-alkyl biradical lifetimes give a chance for the loss of CO to occur. Looking for additional strategies to generate transient biradicals in solids, we studied the solid state photochemistry of four aliphatic, dispiro-substituted 1,4-cyclobutandiones (1a-d) that were expected to react from the singlet state. We hypothesized that the release of ring strain from the small ring carbonyl would make the reverse acyl-alkyl combination disfavored, allowing for the loss of CO to occur efficiently and irreversibly. We report here the results of studies carried out in solution, bulk (powder) crystals, and nanocrystalline photochemistry. We have recently shown that excitation of dispirocyclohexyl-1,3-cyclobutanedione 1c led to the trapping of the intermediate oxyallyl with a half life of about 42 min. Our studies with the three other crystalline derivatives revealed that, while all react efficiently, the remarkably long lifetime of oxyallyl is unique to crystals of 1c.

Salt/ligand-activated low-valent titanium formulations: the 'salt effect' on diastereoselective carbon-carbon bond forming SET reactions

A comprehensive study on the influence of exogenously added electropositive metal salts as promoters/secondary activators on preformed LVT species has resulted in the construction of highly efficient low-valent titanium (LVT) reagents. These salt-activated LVT reagents while exhibiting enhanced chemoselectivity and diastereoselectivity accelerated the reductive olefination rates of aromatic and aliphatic carbonyls under ambient temperature conditions and in much reduced reaction times. The versatility of the salted reagent was further explored in other single electron transfer reactions, namely, imino-pinacol couplings and one-pot synthesis of phenanthrenes from o-alkoxy aromatic carbonyls. We envisage that, in contrast to multiphase heterogeneous colloidal slurries, salt-activated LVT reagents afforded uniformly viscous homogeneous slurries generating a highly reactive monomeric intermetallic LVT complex. Continued judicious exploration of the emerging paradigms by studying the influence of external ligands/auxiliaries/redox agents on LVT reagents, and organometallics in general, will be critical to widen the scope and utility of the classical McMurry reaction and other SET reactions.

Highly active salted low-valent titanium reagents for various SET induced reactions

External addition of inorganic salts (Group I and II metal halides) to the preformed low-valent titanium reagent A (TiCl3-Li-THF) dramatically enhanced its activity. The new reagents were used to carry out various SET reactions including McMurry's olefination at a faster rate even at ambient temperature.

Activation of Low-Valent Titanium Reagents with Iodine: Facile Low-Temperature McMurry Reaction and N/O-Debenzylation/Deallylation

A highly reactive, low-valent titanium (LVT) reagent has been prepared by the addition of substoichiometric amounts of iodine to the LVT species generated by Rieke's method (TiCl3-Li-THF). While the conventional McMurry reaction requires high temperatures and prolonged reaction times for the generation of olefins, the present activated LVT reagent is able to effect the reductive coupling of aliphatic as well as aromatic carbonyls to the corresponding olefins at lower temperatures and much reduced reaction times. The protocol is also useful for the intramolecular coupling reactions leading to the one-step synthesis of heterocycles. The temperature-controlled McMurry reaction provides enhanced diastereoselectivity and features an excellent chemoselectivity. In addition to the McMurry reaction, other SET-induced carbon-heteroatom (O, N) bond cleavages can also be carried out with the activated reagent at a fast rate and at a low temperature in high yields.

A New One-flask Ramberg-Baecklund Reaction

A refined verson of the Meyers' modification of the Ramberg-Baecklund reaction employing the reagent alumina-supported KOH-CBr2F2-ButOH allows α- and α'-hydrogen-bearing sulfones of various structural types to be converted into alkenes.

Oxidative addition of carbon-oxygen and carbon-nitrogen double bonds to WCl2(PMePh2)4. Synthesis of tungsten metallaoxirane and tungsten oxo- and imido-alkylidene complexes

WCl2L4 (1, L = PMePh2) reacts rapidly with a variety of ketones and aldehydes to form bis(η2-ketone) or bis(η2-aldehyde) complexes WCl2(η2-O=CRR′)2L2 (2, 3)

A Convenient Reagent for the Intermolecular Coupling of Aldehydes and Ketones to Form Olefins

When aldehydes or ketones are treated with titanium tetrachloride and amalgamated magnesium turnings in tetrahydrofuran at 0 deg C for 2 h and subsequently under reflux for 24 h, reductive coupling occurs to give olefin in high yield.The optimum ratio of carbonyl substrate to titanium reagent was found to be 1 : 4.Examples of symmetrical and mixed couplings are given.Intramolecular coupling was not successful.

Magnesium- and Titanium-induced Reductive Coupling of Carbonyl Compounds: Efficient Syntheses of Pinacols and Alkenes

Finely dispersed magnesium on graphite was found to be a totally selective single-electron transfer reagent of general utility for the reduction of various kinds of carbonyl and dicarbonyl compounds to pinacols, a reaction quite compatible with a number of functional groups.Similarly, titanium on graphite proved to be a universally applicable reducing agent for the efficient conversion of pinacols, carbonyl and dicarbonyl compounds into alkenes and cycloalkenes respectively and for the cyclization of oxo alkanoates to enol ethers, facilitating and unifying the highly useful McMurry reaction.The practicability of the presently known carbonyl coupling methods is discussed in the light of these results.

FREE RADICAL CHAIN ELIMINATION REAKTION (ERC1). CONVERSION OF VICINAL DINITRO COMPOUNDS OR β-NITRO SULFONES TO OLEFINS WITH TRIBULYLTIN HYDRIDE

Vicinal dinitro compounds (1) or β-nitro sulfones (2) are converted to olefins in good yields on treatment with tributyltin hydride.This elimination proceeds by way of an electron transfer chain mechanism.The elimination from 1 is nonstereospecific and the elimination from 2 is stereospecific.

Thermolysis and photolysis of 3,3:4,4-dibutano-1,2-dioxetane

Thermolysis of 5 x 10-3 M 3,3:4,4-dibutano-1,2-dioxetane 2, Ea = 25.3 +/- 0.3 kcal/mol, ΔS* = 0 +/- 2 eu, in degassed decane solution at 42 deg C produced a 300:1 ratio of cyclopentanone 3:4-pentenal, 4.From the quantum yield of photolysis of 3 to 4, determined to be 0.27 using 313 nm light, it is calculated that 2.5 percent excited 3 is formed on the thermolysis of 2.Photolysis of (>380 nm) 5 x 10-4 M 2 produces a 54:1 ratio of 3:4 corresponding to a 13.5 percent yield of excited 3.Excited state yields determined by measuring luminescence of benzene solution of 2 containing DPA and DBA were 1 x 10-4 percent singlet and 8.7 percent triplet.The reason for the 300 percent discrepancy between the two methods for determining excited state yields is not known.