Facile Ring Expansions of α-Halomethyl β-Keto Esters Mediated with SmI2

Chung, So Hee; Cho, Min Seok; Choi, Jun Young; Kwon, Doo Won; Kim, Yong Hae

doi:10.1055/s-2001-16064

Cited by 21 publications

(2 citation statements)

References 9 publications

(11 reference statements)

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“…It has also been proposed that this intermediate may arise from radical coupling between a ketyl radical generated at the ketone and one generated from the primary iodide. [88] In either case, fragmentation of 172 then delivers cycloheptanone 173, which was isolated in 71 % yield. Interestingly, the mixture of epimeric starting materials 170 was inconsequential, and the product was obtained as a single stereoisomer.…”

Section: Cascade Reactionsmentioning

confidence: 99%

Samarium Diiodide Mediated Reactions in Total Synthesis

2009

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Introduced by Henri Kagan more than three decades ago, samarium diiodide (SmI 2 ) has found increasing applications in chemical synthesis. This single-electron reducing agent has been particularly useful in C-C bond formations, including those found in total synthesis endeavors. This Review highlights selected applications of SmI 2 in total synthesis, with special emphasis on novel transformations and mechanistic considerations. The examples discussed are both illustrative of the power of this reagent in complex molecule construction and inspirational for the design of synthetic strategies toward such targets, both natural and designed.

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Section: Cascade Reactionsmentioning

confidence: 99%

Samarium Diiodide Mediated Reactions in Total Synthesis

2009

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“…These methods are very efficient for the construction of medium-sized cyclic compounds, and the reactions are very attractive, since these types of ring expansion are specific radical reactions. Recently, treatment of α-halomethyl cyclic β-keto esters with SmI 2 in THF in the presence of an activator such as MeOH, HMPA, or NiI 2 was reported to give the corresponding one-carbon ring-expanded products in good to moderate yields . However, SmI 2 is rather sensitive to air, and has to be kept in a tightly closed container under an inert atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Zinc- and Indium-Mediated Ring-Expansion Reaction of α-Halomethyl Cyclic β-Keto Esters in Aqueous Alcohol

2003

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Radical ring-expansion reaction of various alpha-halomethyl cyclic beta-keto esters and alpha-halomethyl benzocyclic beta-keto esters and chain-extension reaction of alpha-halomethyl beta-keto esters with zinc powder and indium powder in refluxing aqueous alcohol were carried out to generate the corresponding ring-expansion and chain-extension products. As the results indicate, it was found zinc powder was more effective than indium powder to give the corresponding ring-expanded products in quite good yields. Moreover, the addition of zinc bromide as Lewis acid showed an increase of the yields, depending on the substrates. The present reaction conditions are highly effective, simple, and environmentally friendly.

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Preparation of Difunctional Compounds

2003

Compendium of Organic Synthetic Methods

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Facile Ring Expansions of α-Halomethyl β-Keto Esters Mediated with SmI2

Abstract: Treatment of a-halomethyl b-keto esters with SmI 2 afforded their corresponding one-carbon expanded products with the aids of HMPA or NiI 2 .

Cited by 21 publications

References 9 publications

Samarium Diiodide Mediated Reactions in Total Synthesis

Samarium Diiodide Mediated Reactions in Total Synthesis

Zinc- and Indium-Mediated Ring-Expansion Reaction of α-Halomethyl Cyclic β-Keto Esters in Aqueous Alcohol

Preparation of Difunctional Compounds

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