Vinylogous Wolff rearrangement of cyclic β,γ-unsaturated diazomethyl ketones: a new synthetic method for angularly functionalised polycyclic systems

Saha, Bijali; Bhattacharjee, G.; Ghatak, Usha Ranjan

doi:10.1039/p19880000939

Cited by 9 publications

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“…[523] Insertion of the metal carbenoid into OϪH bonds, ϪCOϪCHN 2 Ǟ ϪCOϪCH 2 OR, is competitive in the catalyzed reactions. [523] ''Inert'' solvents, with 0.2Ϫ2% alcohol added, have been used to minimize the formation of α-alkoxyketones (Table 8). Acyclic precursors, such as 765, gave only modest yields of vinylogous products.…”

Section: Vinylogous Wolff Rearrangementsmentioning

confidence: 99%

100 Years of the Wolff Rearrangement

2002

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The conversion of α‐diazo ketones into ketenes, and products derived therefrom, was discovered by Wolff in 1902. Major applications of the Wolff rearrangement, such as the Arndt−Eistert reaction (homologation of carboxylic acids) and the ring contraction of cyclic ketones, have been with us for some while. Nevertheless, substantial progress has been made recently. The reaction mechanism has been explored by means of matrix isolation, time‐resolved spectroscopy, and computation. Full retention of configuration of the migrating group has been established by using enantioselective chromatography. The Arndt−Eistert reaction has witnessed a renaissance in the field of natural products, in particular β‐amino acids and β‐peptides. Ring‐contracting Wolff rearrangements and ketene cycloadditions have been applied in syntheses of increasingly complex, biologically active target molecules. These accomplishments, as well as unsolved problems, are addressed in the present review. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

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Section: Vinylogous Wolff Rearrangementsmentioning

confidence: 99%

100 Years of the Wolff Rearrangement

2002

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Wolff Rearrangement

2010

Comprehensive Organic Name Reactions and Reagents

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The thermal, photochemical or catalytic transformation of α‐diazoketones into ketenes is generally known as the Wolff rearrangement. The readiness of Wolff rearrangement is probably due to the evolution of a nitrogen molecule, forming a carbenic intermediate. Several transition metal catalysts have been used and it has been reported that the copper salt can facilitates the generation of a carbene intermediate and lower the energy barrier for the Wolff rearrangement, however, a silver salt is even better than the copper salt for such purpose. It has been reported that cyclic α‐diazoketones undergo the Wolff rearrangement to give the ring‐contracted cyclic carboxylic acids. The study finds that in the case of β‐oxy‐α‐diazoketones, such as β‐hydroxy‐α‐diazoketones, the regular alkyl migration in the normal Wolff rearrangement is depressed by the competitive 1,2‐H shift from hydroxyl to carbene, leading to 100% of vinyl ketones. In terms of the structures of α‐diazoketones, α‐diazo malonates often form vinyl alkyl ethers due to the loss of carbon monoxide. Furthermore, both carbon monoxide and oxygen are reported to suppress the Wolff rearrangement. It has also been reported that 2‐diazodibenzyl malonate undergoes the Wolff rearrangement more easily than 2‐diazodimethyl malonate in the presence of a transition metal catalyst. The reversal of the Wolff rearrangement, known as the retro ‐Wolff rearrangement, has also been reported. This reaction has very broad application in organic synthesis as well as in industrial imaging.

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Metal Catalysed Cyclopropanation

McKervey

2009

Patai's Chemistry of Functional Groups

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Introduction Cyclopropanation Using Diazoalkanes Cyclopropanation Using Diazocarbonyl Compounds Cyclopropanation Using Other Precursors Chemoselectivity in Metal Catalysed Cyclopropanation Regioselectivity in Metal Catalysed Cyclopropanation Stereochemical Features of Alkene Cyclopropanation Conclusion

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Vinylogous Wolff rearrangement of cyclic β,γ-unsaturated diazomethyl ketones: a new synthetic method for angularly functionalised polycyclic systems

Cited by 9 publications

References 1 publication

100 Years of the Wolff Rearrangement

100 Years of the Wolff Rearrangement

Wolff Rearrangement

Metal Catalysed Cyclopropanation

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