- Rapid Entry into Biologically Relevant α,α-Difluoroalkylphosphonates Bearing Allyl Protection-Deblocking under Ru(II)/(IV)-Catalysis
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A convenient synthetic route to α,α-difluoroalkylphosphonates is described. Structurally diverse aldehydes are condensed with LiF2CP(O)(OCH2CH-CH2)2. The resultant alcohols are captured as the pentafluorophenyl thionocarbonates and efficiently deoxygenated with HSnBu3, BEt3, and O2, and then smoothly deblocked with CpRu(IV)(π-allyl)quinoline-2-carboxylate (1-2 mol %) in methanol as an allyl cation scavenger. These mild deprotection conditions provide access to free α,α-difluoroalkylphosphonates in nearly quantitative yield. This methodology is used to rapidly construct new bis-α,α-difluoroalkyl phosphonate inhibitors of PTPIB (protein phosphotyrosine phosphatase-1B).
- Panigrahi, Kaushik,Fei, Xiang,Kitamura, Masato,Berkowitz, David B.
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supporting information
p. 9846 - 9851
(2019/12/24)
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- An unusual solvent effect on the regiochemical outcome (N-9 versus N-7) of guanine glycosylation using Robins' reagent (2-N-acetyl-6-O- diphenylcarbamoylguanine)
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An unexpectedly low N-9/N-7 regioselectivity was obtained when Robins reagent (2-N-acetyl-6-O-diphenylcarbamoylguanine) was coupled with a D- glucosamine derivative under trimethylsilyl trifluoromethanesulfonate activation. An unprecedented solvent effect (toluene versus dichloroethane) on the N-9/N-7 ratio was also observed in the same study. The use of 2-N- acetyl-6-O-benzylguanine to successfully overcome the above regioselectivity problem is described. (C) 2000 Elsevier Science Ltd.
- Cheung, Adrian Wai-Hing,Sidduri, Achyutharao,Garofalo, Lisa M.,Goodnow Jr., Robert A.
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p. 3303 - 3307
(2007/10/03)
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