project out toward the DNA minor groove in the ternary “cleavage complex.” Compound 4 was synthesized in order to test this DNA-threading scenario. It was found unexpectedly that an alkenyl substituent on the C11 position was autoxidatively cleaved under basic conditions to afford a ketone. A possible mechanism for this unusual oxidative cleavage was proposed on the basis of the studies of a 9-fluoredene
Synthesis of 9-Alkylidene-9<i>H</i>-fluorenes by a Novel, Palladium-Catalyzed Cascade Reaction of Aryl Halides and 1-Aryl-1-alkynes
作者:Richard C. Larock、Qingping Tian
DOI:10.1021/jo010561o
日期:2001.11.1
In the presence of a palladium catalyst and NaOAc, aryl iodides react with 1-aryl-1-alkynes to afford 9-alkylidene-9H-fluorenes in good yields. The products from this reaction are highly dependent on the base employed. This process appears to involve (1) oxidative addition of the aryl iodide to Pd(0), (2) alkyne insertion, (3) rearrangement of the resulting vinylic palladium intermediate to an arylpalladium
Synthesis of 9-Alkylidene-9<i>H</i>-fluorenes by a Novel Palladium-Catalyzed Rearrangement
作者:Qingping Tian、Richard C. Larock
DOI:10.1021/ol000220h
日期:2000.10.1
iodides react with 1-aryl-1-alkynes to afford 9-alkylidene-9H-fluorenes in good yields. This process appears to involve (1) oxidative addition of the aryl iodide to Pd(0), (2) alkyne insertion, (3) rearrangement of the resulting vinylic palladium intermediate to an arylpalladium species, and (4) aryl-aryl coupling with simultaneous regeneration of the Pd(0) catalyst.
O'Ferrall, Rory A. More; Larkin, Finbar; Walsh, Peter, Journal of the Chemical Society. Perkin transactions II, 1982, p. 1573 - 1580
作者:O'Ferrall, Rory A. More、Larkin, Finbar、Walsh, Peter
DOI:——
日期:——
Development of a Robust Protocol for the Determination of Weak Acids’ p<i>K</i><sub>a</sub> Values in DMSO
作者:Sebastian T. Jung、Joachim Podlech
DOI:10.1021/acs.joc.0c00909
日期:2020.8.21
Two methods for the determination of pKa values of weakacids are described, a direct titration with dimsyl potassium in the presence of an indicator and a back-titration in which an analyte/indicator mixture is deprotonated and then titrated with ammonium chloride. Both methods have been validated by measuring pKa values of compounds, for which values had been determined previously. The back-titration
描述了两种测定弱酸的p K a值的方法,一种是在指示剂存在下用二甲基钾直接滴定,另一种是将分析物/指示剂混合物去质子化然后用氯化铵滴定的反滴定法。两种方法均已通过测量化合物的p K a值进行了验证,此前已确定了该值。采用反滴定法测量了两个1,3-二噻吩衍生的二亚砜和一砜的p K a值。