The specific rates of solvolysis of propargyl chloroformate (1) are analyzed in 22 solvents of widely varying nucleophilicity and ionizing power values at 25.0 °C using the extended Grunwald-Winstein equation. Sensitivities to solvent nucleophilicity (l) of 1.37 and to solvent ionizing power (m) of 0.47 suggest a bimolecular process with the formation of a tetrahedral intermediate. A plot of the rates of solvolysis of 1 against those previously reported for phenyl chloroformate (2) results in a correlation coefficient (R) of 0.996, a slope of 0.86, and an F-test value of 2161. The unequivocal correlation between these two substrates attest that the stepwise association-dissociation (A(N) + D(N)) mechanism previously proposed for 2 is also operative in 1.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3111911 | PMC |
| http://dx.doi.org/10.5402/2011/767141 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Divergent Stereocontrolled Synthesis of the Enantiopure Tetracyclic Cores of Asparagamine A and Stemofoline via an Intramolecular 2-Propylidine-1,3-(bis)silane Bicyclization.
J Org Chem
October 2015
Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana 59717, United States.
A concise and highly diastereoselective synthesis of the polyfused tetracyclic cores of the Stemona alkaloids asparagamine A and stemofoline that relies on a 2-propylidine-1,3-(bis)silane bicyclization onto a enantiodefined pyrrolidine 2,5-di(cation) equivalent derived from l-malic acid is reported. A crucial feature of this divergent synthetic approach involves the solvolysis of a transient and highly labile tertiary-propargylic hydroxylactam trifluoroacetate in the strongly ionizing medium 5 M LiClO4/Et2O. The acyliminium ion generated in this manner undergoes stereospecific interception by the aforementioned (bis)silane nucleophile.
View Article and Find Full Text PDFUse of Linear Free Energy Relationships (LFERs) to elucidate the mechanisms of reaction of a γ-methyl-β-alkynyl and an ortho-substituted aryl chloroformate ester.
Int J Mol Sci
February 2015
Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115, USA.
The specific rates of solvolysis of 2-butyn-1-yl-chloroformate (1) and 2-methoxyphenyl chloroformate (2) are studied at 25.0 °C in a series of binary aqueousorganic mixtures. The rates of reaction obtained are then analyzed using the extended Grunwald-Winstein (G-W) equation and the results are compared to previously published G-W analyses for phenyl chloroformate (3), propargyl chloroformate (4), p-methoxyphenyl choroformate (5), and p-nitrophenyl chloroformate (6).
View Article and Find Full Text PDFA Study of Solvent Effects in the Solvolysis of Propargyl Chloroformate.
ISRN Org Chem
January 2011
Department of Chemistry, Wesley College, 120 N. State Street, Dover, Delaware 19901-3875, USA.
The specific rates of solvolysis of propargyl chloroformate (1) are analyzed in 22 solvents of widely varying nucleophilicity and ionizing power values at 25.0 °C using the extended Grunwald-Winstein equation. Sensitivities to solvent nucleophilicity (l) of 1.
View Article and Find Full Text PDFStereoselective Total Synthesis of the Pseudopterolide Kallolide A.
J Org Chem
August 1998
Department of Chemistry University of Virginia, Charlottesville, Virginia 22901.
A total synthesis of the pseudopterolides, kallolide A (36) and kallolide A acetate (35), has been achieved. The racemic forms were prepared from the syn adduct 20 of furan 13 and stannane 17 (BF(3).OEt(2)-promoted addition) via the 15-membered propargylic allylic ether 25.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!