Mechanism of the reaction of trialkyl phosphites with α-halogenoacetophenones in alcoholic solvents
作者:Imre Petneházy、György Keglevich、László Tőke、Harry R. Hudson
DOI:10.1039/p29880000127
日期:——
suggested betaine as a common intermediate in alcoholic solution. Further reaction then involvesrearrangement to give the vinyloxyphosphonium species (and hence the Perkow product) or protonation followed by dealkylation to give the α-hydroxyphosphonate. Evidence for the possible formation of dehalogenated ketone via solvolysis of the α-hydroxyphosphonium intermediate is also presented.
Selective Alkenylation and Hydroalkenylation of Enol Phosphates through Direct CH Functionalization
作者:Xu‐Hong Hu、Xiao‐Fei Yang、Teck‐Peng Loh
DOI:10.1002/anie.201506437
日期:2015.12.14
Rh‐catalyzed direct CH functionalization reaction of enol phosphates was developed. The method is applicable to a variety of coupling partners, including activatedalkenes, alkynes, and allenes, and leads to the formation of various valuable alkenylated and hydroalkenylated enol phosphates through the action of the phosphate directing group. The versatility and utility of the coupling products were demonstrated
The reactions of phenacyl benzoates, X–C6H4COCH2OCOC6H4–Y (1a–i), with trialkylphosphites (2a–c) giving dialkyl 1-arylvinyl phosphates (3a–d) in high yields were studied kinetically using the GLC technique. The overall reactions are second order, and exhibit a moderate solvent effect and catalysis upon the addition of certain organic acids. The activation energy, Ea=16.5 kcal/mol, and entropy, ΔS\eweq=−38
Catalyst-Free Difunctionalization of Activated Alkenes in Water: Efficient Synthesis of β-Keto Sulfides and Sulfones
作者:Huamin Wang、Guangyu Wang、Qingquan Lu、Chien-Wei Chiang、Pan Peng、Jiufu Zhou、Aiwen Lei
DOI:10.1002/chem.201603041
日期:2016.10.4
Difunctionalization of activated alkenes, a powerful strategy in chemical synthesis, has been accomplished for direct synthesis of a series of β‐keto sulfides and β‐keto sulfones. The transformation, mediated by O2, proceeds smoothly in water and without any catalyst. Prominent advantages of this method include mild reaction conditions, purification simplicity, and gram‐scale synthesis, underlining
Magnesium hydride, generated in situ by solvothermal treatment of sodium hydride and magnesium iodide in tetrahydrofuran, was found capable of inducing regio and stereocontrolled hydromagnesiation of 2-aryl-1,3-dienes to form allylmagnesium species. Downstream functionalization of the resulting allylmagnesium species with various electrophiles provided synthetically valuable synthons such as homoallylic