- Practical large-scale preparation of (±)-2-exo-norbornyl carboxylic acid and its improved isolation as the sodium salt
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A practical, robust, and high-yielding three-step-one-pot procedure for the diastereoselective synthesis of (±)-2-exo-norbornyl carboxylic acid starting from norbornylene has been found and demonstrated on multikilogram scale, setting a new benchmark for
- Gu, Jianxin,Storz, Thomas,Vyverberg, Frederick,Wu, Charles,Varsolona, Richard J.,Sutherland, Karen
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experimental part
p. 942 - 945
(2012/07/14)
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- Kinetics and mechanism of acid-catalyzed hydration of 5-hydroxymethyl- and 5-phenoxymethylnorborn-2-enes
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The disappearance rate constants for exo- and endo-5-hydroxymethylnorborn-2-enes (3 and 4) and exo- and endo-5-phenoxymethylnorborn-2-enes (5 and 6) were measured in aqueous perchloric acid by a capillary GC method at different temperatures and acid concentrations. The rate constants, activation parameters, excess acidity plots and products (for 3 and 4 only) are in agreement with the rate-determining protonation of the double bond (AdE2 mechanism). No proof of endo protonation of the double bond via the protonated endo-5-CH2OH group was obtained. The excess acidity plots were corrected according to the partial protonation of the hydroxylic or ether oxygen atom. In the case of 3 and 4, the slope parameter m?, indicative of the transition state, decreases slightly with increasing temperature, the intercept parameter log (ko/M-1s-1) depends reasonably on the temperature, and the protonation site parameters of the hydroxymethyl group, m′ and pKS′H+, are temperature-independent. The corresponding parameters for 5 and 6 at 303 K are normal except the peculiar pKS′H+ values, ca. -2.5.
- Lajunen, Martti,Latva-Nirva, Esa
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p. 719 - 723
(2007/10/03)
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- SILICON IN SYTHESIS-17 CHLROMETHYL(TRIMETHYLSILYL)LITHIUM-A NEW REAGENT FOR THE DIRECT CONVERSION OF ALDEHYDES AND KETONES INTO α,β-EPOXYTRIMETHYLSILANES
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Treatment of chloromethyltrimethylsilane 1 with sec-BuLi at -78 deg produces chloromethyl(trimethylsilyl)lithium 4.Treatment of 4 with a wide range of aldehydes and ketones gives α,β-epoxytrimethylsilanes 5-28, which on acidic hydrolysis give homologated aldehydes.
- Burford, Clifford,Cooke, Frank,Roy, Glenn,Magnus, Philip
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p. 867 - 876
(2007/10/02)
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