15619-34-8Relevant articles and documents
Kinetic studies of acetate exchange in trans-4-acetoxy-[η3-(1,2,3)-cyclohexenyl]palladium complexes. Relevance for asymmetric 1,4-oxidation reactions
Cotton, Hanna K.,Verboom, Renzo C.,Johansson, Lars,Plietker, Bernd J.,B?ckvall, Jan-E.
, p. 3367 - 3375 (2002)
The acetate/acetate-d3 exchange reaction of the ring-bonded acetate of bis(4-acetoxy-[η3-(1,2,3)-cyclohexenyl]palladium acetate-d3 complexes 1a-c was studied in acetic acid solutions using 1H NMR spectroscopy. The reactions followed first-order kinetics in palladium, and the rates were highly affected by the presence of methanesulfonic acid or lithium acetate. The nature of the substituent in the 2-position of the complex was found to have a large impact on the reaction rate. Complexes 1a-c are observed intermediates in the benzoquinone-assisted palladium(II)-catalyzed 1,4-diacetoxylation reaction of 1,3-dienes. Complex 1b was treated with stoichiometric amounts of the enantiomerically pure ligand (S)-(+)-2-(4′-fluorophenylsulfinyl)-1,4-benzoquinone 4 under conditions where no exchange reaction occurs. Kinetic resolution was observed, implying that the two enantiomers of 1b reacted to trans-1,4-diacetoxy-2-phenyl-2-cyclohexene with different rates. Attempts to demonstrate dynamic kinetic resolution in stoichiometric reactions between 1b and 4 were unsuccessful. The major reason for this is presumably that with lithium acetate the equilibrium reaction between the two enantiomers of 1b is too slow compared to the chiral benzoquinone-induced attack of acetate to give the products. Under very acidic conditions the decomposition of the (π-allyl)palladium complex is faster than benzoquinone-induced product formation. This scenario is in full agreement with our observed rates.
Three-Component Difunctionalization of Cyclohexenyl Triflates: Direct Access to Versatile Cyclohexenes via Cyclohexynes
Cho, Seoyoung,McLaren, E. J.,Wang, Qiu
, p. 26332 - 26336 (2021/11/10)
Difunctionalization of strained cyclic alkynes presents a powerful strategy to build richly functionalized cyclic alkenes in an expedient fashion. Herein we disclose an efficient and flexible approach to achieve carbohalogenation, dicarbofunctionalization, aminohalogenation and aminocarbonation of readily available cyclohexenyl triflates. We have demonstrated the novel use of zincate base/nucleophile system for effective formation of key cyclohexyne intermediates and selective addition of various carbon and nitrogen nucleophiles. Importantly, leveraging the resulting organozincates enables the incorporation of a broad range of electrophilic partners to deliver structurally diverse cyclohexene motifs. The importance and utility of this method is also exemplified by the modularity of this approach and the ease in which even highly complex polycyclic scaffolds can be accessed in one step.
IBS-catalyzed oxidative rearrangement of tertiary allylic alcohols to enones with oxone
Uyanik, Muhammet,Fukatsu, Ryota,Ishihara, Kazuaki
supporting information; experimental part, p. 3470 - 3473 (2009/12/05)
A 2-iodoxybenzenesulfonic acid (IBS)-catalyzed oxidative rearrangement of tertiary allylic alcohols to enones with powdered Oxone in the presence of potassium carbonate and tetrabutylammonium hydrogen sulfate has been developed.
