38212-18-9Relevant articles and documents
Beyond the Tebbe Olefination: Direct Transformation of Esters into Ketones or Alkenes
Dom?alska-Pieczykolan, Anna M.,Furman, Bart?omiej
supporting information, p. 730 - 736 (2020/04/08)
A direct, effective, and operationally simple transformation of esters into ketones or alkenes by the exclusive action of Tebbe's reagent has been developed. The transformation utilizes the dual character of Tebbe's reagent as both a methylenation agent and a rearrangement catalyst in the reaction of a wide range of substituted vinyl ethers. The resulting transformation involves sequential methylenation and rearrangement reactions and it offers a high degree of selectivity toward the synthesis of ketones or alkenes. The scope and limitations of the developed methods have been also examined.
Effect of Lewis acids and low temperature initiators on the allyl transfer reaction involving phthalimido-N-oxyl radical
Patil, Shradha,Chen, Liang,Tanko, James M.
supporting information, p. 7029 - 7033 (2015/01/09)
Previously, we reported allyl transfer reactions of allyl bromide and allyl phthalimido-N-oxyl substrates with hydrocarbons that result in CC bond formation. In both cases, efficient chain transfer processes along with high reaction yields were observed. Since PINO chemistry leads to an environmentally friendly method of hydrocarbon functionalization, additional studies were performed in order to improve the process. To expand the utility of this reaction, we carried out experiments to optimize reaction conditions and tested the effect of Lewis acids and low temperature initiators. Although allyl-PINO substrates reacted slightly slower than the bromides, the reactions were cleaner with little or no side products. The chain lengths for these reactions were compromised at lower temperatures, attributable to the high activation energy required for the hydrogen atom abstraction by PINO. The addition of a Lewis acid catalyst (AlCl3) improves the product yield and reaction rate, possibly due to the formation of a PINO/AlCl3 complex which lowers the activation energy for hydrogen abstraction step.
C-H bond functionalization with the formation of a C-C bond: A free radical condensation reaction based on the phthalimido-N-oxyl radical
Patil, Shradha,Chen, Liang,Tanko, James M.
, p. 502 - 505 (2014/02/14)
The development of a new chemical process that effects the conversion RH + C=C-C-X → R-C-C=C + HX, in which X is the phthalimido-N-oxyl radical (PINO·), is reported. The reaction yields are high, mass balances are excellent, and C-H bond functionalization and C-C bond formation are achieved in a single transformation. The byproduct of the reaction, N-hydroxyphthalimide, precipitates from solution and can be easily removed by simple filtration (and recycled). The kinetic chain lengths are shorter and the reaction times are longer (relative to those of the analogous reactions of allyl bromides), most likely because PINO· is a less-reactive hydrogen-atom abstractor. There appears to be no significant difference in efficiency in the addition-elimination steps. Competition experiments reveal that Br· and PINO· are comparable in leaving group ability. The introduction of a new chain carrier, the phthalimido-N-oxyl radical (PINO·), leads to an improved chain reaction. This chain reaction is successful and high reaction yields are reported for the functionalization of hydrocarbons. Kinetic studies reveal that this reaction is an efficient chain process, and the leaving group ability of PINO · is comparable to that of Br·. Copyright
