A Highly Efficient Access to Spiroketals, Mono-unsaturated Spiroketals, and Furans: Hg(II)-Catalyzed Cyclization of Alkyne Diols and Triols

Kontham, Ravindar; Reddy, Maddi Sridhar; Deslongchamps, Pierre

doi:10.1021/ol201102x

Cited by 61 publications

(35 citation statements)

References 37 publications

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“…[1] Prominent and recent examples include the spongistatins/altohyrtins. [6] A similar cyclization of propargylic triols was reported by Aponick, [7] and later extended by Deslongchamps [8] (Scheme 1). A double bond can be an important functional group for the introduction of additional substituents into a spiroketal substructure.…”

Section: Introductionmentioning

confidence: 66%

Gold(I)‐, Palladium(II)‐, Platinum(II)‐, and Mercury(II)‐Catalysed Spirocyclization of 1,3‐Enynediols: Reaction Scope

Zhdanko¹,

Maier²

2014

Eur J Org Chem

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The spirocyclization of different 1,3‐enynediols was investigated. The reaction was only efficient for the synthesis of [5,6]‐spiroacetals. In this case, the reaction was characterized by almost quantitative yields, short reaction times, and low catalyst loadings (0.5–1 %). When the synthesis of [6,6]‐spiroacetals was attempted, the reaction suffered from poor regioselectivity and a higher propensity of the intermediate dienol ethers to decompose under the acidic conditions, and it became no longer viable. But it is possible to generate the dienol ethers cleanly under milder conditions as a mixture of regioisomers. This striking difference in reaction efficiency was explained by the unstable dienol ethers cyclizing more quickly to give [5,6]‐spiroacetals than to give [6,6]‐spiroacetals. In this study, the successful application of a new cationic palladium pincer complex for electrophilic alkyne activation at room temperature has been demonstrated for the first time.

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Section: Introductionmentioning

confidence: 66%

Gold(I)‐, Palladium(II)‐, Platinum(II)‐, and Mercury(II)‐Catalysed Spirocyclization of 1,3‐Enynediols: Reaction Scope

Zhdanko¹,

Maier²

2014

Eur J Org Chem

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“…Delay in filtration or increase in temperature caused the catalyst to decompose and made the product difficult to purify. Subsequent to our synthesis of 12 a very similar synthesis of the same compound was published by Deslongchamps and coworkers [32], which only differed in that the cyclisation of 11 to 12 in excellent yield was catalysed by Hg(II), instead of Au(I).…”

Section: Resultsmentioning

confidence: 95%

Gold(I)-catalysed synthesis of a furan analogue of thiamine pyrophosphate

Iqbal¹,

Sahraoui²,

Leeper³

2014

Beilstein J. Org. Chem.

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SummaryAn analogue of thiamine having a furan ring in place of the thiazolium ring has been synthesised by a short and efficient route, involving gold(I)-catalysed cyclisation of an alkynyl alcohol to form the furan ring. The furan analogue of thiamine diphosphate (ThDP) was also made and tested for binding to and inhibition of pyruvate decarboxylase (PDC) from Zymomonas mobilis (overexpressed in E. coli with a N-terminal His-tag). It is a very strong inhibitor, with a K i value of 32.5 pM. It was also shown that the furan analogue of thiamine can be functionalised at the C-2 position, which will allow access to mimics of reaction intermediates of various ThDP-dependent enzymes.

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“…176 In 2011, Deslongchamps reported a highly efficient Hg(II)-catalyzed cycloisomerization–elimination reaction of 3-alkynyl-1,2-diols into furans. 177 …”

Section: Synthesis Of Furansmentioning

confidence: 99%