Phenanthroline and tert-butoxide have been established as powerful radical initiators in reactions such as the S(RN)1-type coupling reactions due to the cooperation of large heteroarenes and a special feature of tert-butoxide. The first phenanthroline-tert-butoxide-catalyzed transition-metal-free allylic isomerization is described. The resulting ketones are key intermediates for indenes. The control experiments rule out the base-promoted allylic anion pathway. The radical pathway is supported by experimental evidence that includes kinetic study, kinetic isotope effect, isotope-labeling experiments, trapping experiments, and EPR experiments.
Phenanthroline and tert-butoxide have been established as powerful radical initiators in reactions such as the S(RN)1-type coupling reactions due to the cooperation of large heteroarenes and a special feature of tert-butoxide. The first phenanthroline-tert-butoxide-catalyzed transition-metal-free allylic isomerization is described. The resulting ketones are key intermediates for indenes. The control experiments rule out the base-promoted allylic anion pathway. The radical pathway is supported by experimental evidence that includes kinetic study, kinetic isotope effect, isotope-labeling experiments, trapping experiments, and EPR experiments.
Dirhodium(<scp>ii</scp>)/P(<i>t</i>-Bu)<sub>3</sub> catalyzed tandem reaction of α,β-unsaturated aldehydes with arylboronic acids
作者:Ziling Ma、Yuanhua Wang
DOI:10.1039/c8ob01997e
日期:——
catalyst for the synthesis of aryl alkyl ketones by the tandem reaction of α,β-unsaturated aromatic or aliphatic aldehydes with arylboronic acids. This tandem procedure included arylation followed by the isomerization reaction. This method exhibits good functional group tolerance and has a broad substrate scope. With the conjugated aldehydes, the one-step synthesis of γ,δ-unsaturated ketones was realized
allylic C−C σ‐bond cleavage of simple olefins to give valuable cinnamyl aldehydes is reported. 1,2‐Aryl or alkyl migration through allylic C−C bond cleavage occurs in this transformation, which is assisted by an alkyl azide reagent. This method enables O‐atom incorporation into simple unfunctionalized olefins to construct cinnamyl aldehydes. The reaction features simple hydrocarbon substrates, metal‐free
Base-Mediated Cascade Rearrangements of Aryl-Substituted Diallyl Ethers
作者:Jolene P. Reid、Catherine A. McAdam、Adam J. S. Johnston、Matthew N. Grayson、Jonathan M. Goodman、Matthew J. Cook
DOI:10.1021/jo502403n
日期:2015.2.6
Two base-mediated cascade rearrangement reactions of diallyl ethers were developed leading to selective [2,3]-Wittig–oxy-Cope and isomerization–Claisen rearrangements. Both diaryl and arylsilyl-substituted 1,3-substituted propenyl substrates were examined, and each exhibits unique reactivity and different reaction pathways. Detailed mechanistic and computational analysis was conducted, which demonstrated