Photolysis of substituted cycloenones. Part 1. 5-Hydroxycyclopentenones

Gowda, G. Byre; McMurry, T. Brian H.

doi:10.1039/p19790000274

Cited by 7 publications

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“…The reactions of 2-substituted 1-(1-alkynyl)cyclopropanols were carried out by the same procedure as described for the stoichiometric reaction of unsubsituted 1-alkynylcyclopropanols 1 . 8a and 9a are known in the literatures. Full data of these compounds are described in the Supporting Information.…”

Section: Methodsmentioning

confidence: 99%

Rearrangement of 1-(1-Alkynyl)cyclopropanols to 2-Cyclopentenones via Their Hexacarbonyldicobalt Complexes. A New Use of Alkyne−Co₂(CO)₆ Complexes in Organic Synthesis

et al. 1998

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A novel rearrangement of 1-(1-alkynyl)cyclopropanols to 2-cyclopenten-1-ones proceeded on complexation of their alkynyl part with octacarbonyldicobalt (Co 2 (CO 8 )). 1-(1-Alkynyl)cyclopropanols with a wide range of substituents on their alkyne terminus rearranged to the corresponding 3-substituted 2-cyclopenten-1-ones in good yield. In case of the reactions of 1-alkynylcyclopropanols with an alkyl substituent on the cyclopropane ring, either 4-substituted or 5-substituted 2-cyclopenten-1-ones could be selectively obtained by appropriate choice of stereochemistry and protective group of the substrates. This rearrangement was successfully applied to cyclopentenone annulation reactions onto cycloalkenes. An efficient synthesis of alkynylsubstituted bicyclo[n.1.0]alkanol derivatives from the corresponding cycloalkenes according to Danheiser's protocol was developed, and bicyclic cyclopentenones were obtained in moderate to good yield by applying to these the cobalt-mediated rearrangement. Furthermore, the rearrangement was found to proceed catalytically on addition of triaryl phosphite as a ligand. In particular, when tri(o-isopropylphenyl) phosphite was used as ligand, 5-10 mol % of Co 2 (CO) 8 and 10-20 mol % of the phosphite sufficed for the efficient conversion of 1-alkynylcyclopropanols to 2-cyclopentenones. Mechanistic studies revealed that the rate-determining step was the thermal or oxidative dissociation of a carbonyl ligand from the alkyne-Co 2 (CO) 6 complex and that the coordinately unsaturated cobalt moiety so-formed inserted into the neighboring carbon-carbon bond of the cyclopropane to give a metallacyclic intermediate. This further rearranged to a metallacyclohexanone intermediate, which gave the cyclopentenone with liberation of a coordinatively unsaturated cobalt species.

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Section: Methodsmentioning

confidence: 99%

Rearrangement of 1-(1-Alkynyl)cyclopropanols to 2-Cyclopentenones via Their Hexacarbonyldicobalt Complexes. A New Use of Alkyne−Co₂(CO)₆ Complexes in Organic Synthesis

et al. 1998

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“…718/0.7 mbar. IR: 2967, 2930, 2869, 1741, 1470, 1450, 1410, 1382, 1360, 1268, 1226, 1144, 1126, 1060, 918, 865, 809, 774, 710, 4 Cl soln. to neutrality.…”

Section: Experimental Partmentioning

confidence: 99%

“…sat. NH 4 Cl soln., dried, and concentrated. Bulb-to-bulb distillation afforded pure ketone 10 (67%).…”

Section: Experimental Partmentioning

confidence: 99%

Alternative Synthesis of 2‐Hydroxy‐3,5,5‐trimethylcyclopent‐2‐en‐1‐one

Chapuis

Saint-Léger

2010

Helvetica Chimica Acta

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The 2-hydroxy-3,5,5-trimethylcyclopent-2-en-1-one (1) was synthesized in 42% yield by rearrangement of epoxy ketone 10 on treatment with BF 3 · Et 2 O under anhydrous conditions. Intermediate 10 was available from the known enone 8, either via direct epoxidation (60% H 2 O 2 , NaOH, MeOH; yield 50%), or via reduction to the corresponding allylic alcohol 14 (LiAlH 4 , THF), followed by epoxidation ([VO(acac) 2 ], t BuOOH) and reoxidation under Swern conditions, in 37% total yield.

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“…13). Photolyses were carried out using a Hanovia 460-W medium pressure mercury lamp, and a Pyrex filter.…”

Section: Methodsmentioning

confidence: 99%

Photochemistry of substituted cyclic enones. Part 6. Photochemical reactions of 5-arylmethyl-3-phenylcyclopent-2-enones. A photostationary state

Clements¹,

McMurry²

1987

Can. J. Chem.

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. Can. J. Chem. 65, 18 10 (1987).Photolysis of 5-(1-and 2-naphthylmethy1)-3-phenylcyclopent-2-ens affords [2 + 21 cycloaddition products, the 7,8-and 5,6-benzo-fused l0-phenyltetracyclo[7.2.1.03~10.04~9]dodeca-5,7-dien-2-ones respectively, in equilibrium with the starting enones. A similar dibenzo-fused photoproduct is formed from the corresponding 9-phenanthrylmethyl substituted cyclopentenone. The photoproducts revert to the respective enones on acid treatment, or pyrolysis, and on photolysis. La photolyse des (naphtyl-1 ou -2 methyl)-5 phenyl-3 cyclopentine-2 ones conduit i des produits de cycloadditions [2 + 21, soit respectivement les benzo-7,8 ou -5,6 phenyl-10 tttracyclo[7.2.1 .03.10.04.9] dodCcadi&ne-5,7 ones-2, qui sont en tquilibre avec les Cnones de depart. Si l'on part de la cyclopent~none correspondante substitute par une phtnanthryl-9 mtthyle, il se forme un photoproduit similaire qui est fusionni i un dibenzo. Par traitement avec des acides, par pyrolyse ou par photolyse, les photoproduits se retransforment dans leurs hones respectives.[Traduit par la revue]In recent publications (1, 3, 4) we have described the photochemical intramolecular cyclisation of 5-ally1 and substituted 5-allylcyclopentenones. In all these cases the reactions were regiospecific, as far as the direction of addition, but in the case of the compounds with cinnamyl side chains there was loss of stereoselectivity of the phenyl substituent. We wished to discover whether aromatic "double bonds" could be incorporated into cycloaddition products and, if so, whether the regiospecificity would be affected. Furthermore, to our knowledge, no example is known where enone adds onto a naphthalene ring although, where two naphthalene rings are linked by a suitable chain, then photoaddition of the two rings is found (5). SvnthesisThe 5-arylmethyl-3-phenylcyclopentenones were synthesised by standard routes (Scheme 1). The ring closure of the diketo esters involves the hydrolysis of the ester and decarboxylation of the keto acid, followed by cyclisation of the resultant 1,5-diketone. In this way, 5-benzyl-, 5-(1-naphthylmethy1)-, 5-(2-naphthylmethy1)-, and 5-(9-phenanthrylmethy1)-3-phenylcyclopentenones (la-d) were prepared.

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Photolysis of substituted cycloenones. Part 1. 5-Hydroxycyclopentenones

Cited by 7 publications

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Rearrangement of 1-(1-Alkynyl)cyclopropanols to 2-Cyclopentenones via Their Hexacarbonyldicobalt Complexes. A New Use of Alkyne−Co₂(CO)₆ Complexes in Organic Synthesis

Rearrangement of 1-(1-Alkynyl)cyclopropanols to 2-Cyclopentenones via Their Hexacarbonyldicobalt Complexes. A New Use of Alkyne−Co₂(CO)₆ Complexes in Organic Synthesis

Alternative Synthesis of 2‐Hydroxy‐3,5,5‐trimethylcyclopent‐2‐en‐1‐one

Photochemistry of substituted cyclic enones. Part 6. Photochemical reactions of 5-arylmethyl-3-phenylcyclopent-2-enones. A photostationary state

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Photolysis of substituted cycloenones. Part 1. 5-Hydroxycyclopentenones

Cited by 7 publications

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Rearrangement of 1-(1-Alkynyl)cyclopropanols to 2-Cyclopentenones via Their Hexacarbonyldicobalt Complexes. A New Use of Alkyne−Co2(CO)6 Complexes in Organic Synthesis

Rearrangement of 1-(1-Alkynyl)cyclopropanols to 2-Cyclopentenones via Their Hexacarbonyldicobalt Complexes. A New Use of Alkyne−Co2(CO)6 Complexes in Organic Synthesis

Alternative Synthesis of 2‐Hydroxy‐3,5,5‐trimethylcyclopent‐2‐en‐1‐one

Photochemistry of substituted cyclic enones. Part 6. Photochemical reactions of 5-arylmethyl-3-phenylcyclopent-2-enones. A photostationary state

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Rearrangement of 1-(1-Alkynyl)cyclopropanols to 2-Cyclopentenones via Their Hexacarbonyldicobalt Complexes. A New Use of Alkyne−Co₂(CO)₆ Complexes in Organic Synthesis

Rearrangement of 1-(1-Alkynyl)cyclopropanols to 2-Cyclopentenones via Their Hexacarbonyldicobalt Complexes. A New Use of Alkyne−Co₂(CO)₆ Complexes in Organic Synthesis