- Lewis Acid-Activated Reactions of Silyl Ketenes for the Preparation of α-Silyl Carbonyl Compounds
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Silyl-substituted ketenes are attractive molecular building blocks due to their stability and ease of storage, as opposed to unstable alkyl and aryl ketenes. To better understand the reactivity of silyl ketenes and, in turn, their use in the preparation o
- Mitchell, Sarah M.,Xiang, Yuanhui,Matthews, Rachael,Amburgey, Alexis M.,Pentzer, Emily B.
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- Lewis Acid-Activated Reactions of Silyl Ketenes for the Preparation of α-Silyl Carbonyl Compounds
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Silyl-substituted ketenes are attractive molecular building blocks due to their stability and ease of storage, as opposed to unstable alkyl and aryl ketenes. To better understand the reactivity of silyl ketenes and, in turn, their use in the preparation o
- Mitchell, Sarah M.,Xiang, Yuanhui,Matthews, Rachael,Amburgey, Alexis M.,Pentzer, Emily B.
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p. 14461 - 14468
(2019/12/02)
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- Synthesis and Application of Bis-Silylethyl-Derived Phosphate-Protected Fmoc-Phosphotyrosine Derivatives for Peptide Synthesis
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Three Fmoc-phosphotyrosine derivatives with silylethyl-based phosphate protection were synthesized and evaluated for use in peptide synthesis.The stability of these derivatives toward piperidine/DMF (1:4) treatment and their cleavability with TFA solutions were examined.On the basis of these data, the bis-protected Fmoc-phosphotyrosine derivative or Fmoc-Tyr(PO3MDPSE2)-OH, was shown to be the most suitable candidate for the production of phosphotyrosine peptides.The syntheses of phosphotyrosine peptides including one containing Met and Cys are described.
- Chao, Hann-Guang,Bernatowicz, Michael S.,Reiss, Paul D.,Matsueda, Gary R.
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p. 6687 - 6691
(2007/10/02)
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- Methyldiphenylsilylation of Ester and Lactone Enolates
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The reactions of a variety of ester and lactone enolates with methyldiphenylchlorosilane were studied.The C-versus O-silylation, leading to the α-silyl ester or lactone and silyl ketene acetal, respectively, was studied as a function of the structure of the ester or lactone and the reaction conditions.It was found that all simple acetates are C-silylated irrespective of the steric demands of the alcohol portion of the ester.Esters that are monosubstituted in the α-position are cleanly C-silylated with the notable exceptions of ethyl phenylacetate and ethyl phenoxyacetate, both of which give mixtures of C- and O-silylation.The α,α-disubstituted esters give only O-silylation, but the α,α-substituted α-silyl esters are readily prepared by the alkylation of the appropriate monosubstituted α-silylated ester.The reaction of the lithium enolate of ethyl acetate and tert-butyl acetate with (S)-(-)-1-naphthylphenylmethylchlorosilane showed the reaction to occur with inversion of configuration at silicon.Methylation of tert-butyl (1-naphthylphenylmethylsilyl)acetate gave a 91:9 mixture of diastereomeric α-silyl propionates, which could not be separated.It was found that only the γ-lactones gave C-silylation with δ-valerolactone and ε-caprolactone giving O-silylation.
- Larson, Gerald L.,Maldonado, Veronica Cruz de,Fuentes, Lelia M.,Torres, Luz E.
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p. 633 - 639
(2007/10/02)
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