Convergent syntheses of 9-deoxy-12-phenylthioprostanoids and 9-deoxy-Δ<sup>8(12)</sup>-PGD<sub>1</sub>derivatives

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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“…3a , 3b , 3c , 3d , and 3l 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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“…The thermolysis of allylic sulfoxides that are unable to provide a typical syn elimination ( 191 , 192 ) gives rise to 1,3-dienes ( 193 , 194 ) presumably by [2,3]-rearrangement followed by thermal elimination of sulfenic acid, as has been suggested in these cases (Scheme ). , Within synthetic efforts to 9-deoxyprostanoids, the low-yielding preparation of 1,3-dienes by thermolysis of allylic sulfoxides lacking syn hydrogens has been attributed to a sequence of sigmatropic rearrangements . The Reich protocol for the preparation of 1,3-dienes from allylic alcohols has been used in the synthesis of the plant growth regulator (−)-penienone, the natural product (5 R )-thiolactomycin, an inhibitor of fatty acid synthesis, new related inhibitors, and a selectively deuterated cyclononadiene …”

Section: Sulfoxide–sulfenate Rearrangements In Tandem Processesmentioning

confidence: 99%

“…139,140 Within synthetic efforts to 9-deoxyprostanoids, the low-yielding preparation of 1,3-dienes by thermolysis of allylic sulfoxides lacking syn hydrogens has been attributed to a sequence of sigmatropic rearrangements. 141 The Reich protocol for the preparation of 1,3-dienes from allylic alcohols has been used in the synthesis of the plant growth regulator (−)-penienone, 142 the natural product (5R)-thiolactomycin, an inhibitor of fatty acid synthesis, 143 new related inhibitors, 144 and a selectively deuterated cyclononadiene. 145…”

Section: From Allyl Sulfoxidesmentioning

confidence: 99%

From Allylic Sulfoxides to Allylic Sulfenates: Fifty Years of a Never-Ending [2,3]-Sigmatropic Rearrangement

et al. 2017

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The [2,3]-sigmatropic rearrangement of allylic sulfoxides to allylic sulfenates is a reversible process, generally shifted toward the sulfoxide. In the presence of thiophiles, the sulfenate is trapped, and allylic alcohols are obtained under mild conditions. In most cases, a good transfer of stereochemical information through an ordered transition state is obtained. Furthermore, the ease of coupling this process with other versatile, stereocontrolled reactions has enhanced the usefulness of this protocol. This review aims to provide a comprehensive survey of this rearrangement and its application in the synthesis of natural and bioactive products.

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Rearrangements involving sulfenic acids and their derivatives

Braverman

1990

Sulfenic Acids and Derivatives (1990)

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Convergent syntheses of 9-deoxy-12-phenylthioprostanoids and 9-deoxy-Δ⁸⁽¹²⁾-PGD₁derivatives

Cited by 8 publications

References 4 publications

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

From Allylic Sulfoxides to Allylic Sulfenates: Fifty Years of a Never-Ending [2,3]-Sigmatropic Rearrangement

Rearrangements involving sulfenic acids and their derivatives

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Convergent syntheses of 9-deoxy-12-phenylthioprostanoids and 9-deoxy-Δ8(12)-PGD1derivatives

Cited by 8 publications

References 4 publications

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

From Allylic Sulfoxides to Allylic Sulfenates: Fifty Years of a Never-Ending [2,3]-Sigmatropic Rearrangement

Rearrangements involving sulfenic acids and their derivatives

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Convergent syntheses of 9-deoxy-12-phenylthioprostanoids and 9-deoxy-Δ⁸⁽¹²⁾-PGD₁derivatives

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