- Aryne triggered [2,3]-sigmatropic rearrangement of allyl and propargyl thioethers
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An efficient protocol for [2,3]-sigmatropic rearrangement of allyl and propargyl thioethers is reported. The key sulfonium ylide intermediate is in situ formed via S-arylation of arynes. This transition metal-free method allows for ready access to a wide
- Tan, Jiajing,Zheng, Tianyu,Xu, Kun,Liu, Changyao
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p. 4946 - 4950
(2017/07/10)
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- Electrochemical partial fluorination of organic compounds. 80. Synthesis of cyclic α-arylthio-α-monofluorophosphonate esters
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Seven-membered cyclic α-monofluorophosphonate esters such as 2-allyloxy-3-fluoro-3-phenylthio-4,7-dihydro-[1, 2]-oxaphosphinine-2-oxide were successfully synthesized in moderate total yield as 41% from open-chain allyl phosphonates having an α-arylthio group as an electroauxiliary using an alternative sequence of anodic fluorination and ring-closing olefin metathesis (RCM). On the other hand, in an attempt to synthesize an eight-membered analogue, a different type of seven-membered fluorinated cyclic product was formed predominantly by the RCM reaction between the allyloxy groups.
- Cao, Yi,Hidaka, Asami,Tajima, Toshiki,Fuchigami, Toshio
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p. 9614 - 9617
(2007/10/03)
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- Synthesis of novel cyclobutylphosphonic acids as inhibitors of imidazole glycerol phosphate dehydratase
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Diethyl 3-oxocyclobutylphosphonate (5) has been synthesised via a novel one-pot cyclisation reaction of the α-phenylsulphonyl-γ,δ-epoxyphosphonate 8. Addition of 5-lithio-1-trityl-1,2,4-triazole to ketone 5 and deprotection then afforded cis-3-hydroxy-3-(1,2,4-triazol-3-yl])cyclobutylphosphonic acid (cis-4) which showed modest in vitro inhibition of the enzyme imidazole glycerol phosphate dehydratase. In an attempt to obtain the corresponding trans isomer (trans-4), whose inhibitory activity was anticipated to he higher, an efficient three-step synthesis was developed employing base-mediated cyclisation of the γ,δ-epoxy-γ-(1,2,4-triazol-5-yl)phosphonate 35. Although this latter route stereoselectively afforded cis-36, an efficient epimerisation reaction could be subsequently used to obtain the desired trans stereochemistry. However, all attempts at deprotection of trans-36 proceeded with simultaneous re-epimerisation to give the previously prepared cis-4. High level ab initio calculations have been used to rationalise the relative thermodynamic stability of cis-4 and trans-4.
- Norcross, Roger D.,Von Matt, Peter,Kolb, Hartmuth C.,Bellus, Daniel
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p. 10289 - 10312
(2007/10/03)
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