15619-34-8Relevant academic research and scientific papers
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.
Design and scale-up of diels-alder reactions for the practical synthesis of 5-phenylbicyclo[2.2.2]oct-5-en-2-one
Funel, Jacques-Alexis,Schmidt, Gunther,Abele, Stefan
, p. 1420 - 1427 (2011)
Several synthetic pathways towards racemic 5-phenylbicyclo[2.2.2]oct-5-en- 2-one 1 have been devised starting with a Diels-Alder reaction of (cyclohexa-1,5-dien-1-yloxy)trimethylsilane and α-acetoxyacrylonitrile, acrylonitrile, or α-chloroacrylonitrile. The first 'fit-for-purpose' route relied on α-acetoxyacrylonitrile as a dienophile and rapidly delivered kilogram amounts of 1. Process safety data then triggered the development of a scalable Diels-Alder reaction using α-chloroacrylonitrile as the dienophile. This practical and volume-efficient route delivered 1 in a 44% yield in six chemical steps with two isolated intermediates. Notably, neither chromatography nor distillation was required for the multikilogram synthesis of 1.
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.
4-biphenylylcalcium iodide and 9-phenanthrylcalcium bromide: Grignard-type reagents of polycyclic aromatic hydrocarbons
Koehler, Mathias,Langer, Jens,Fischer, Reinald,Goerls, Helmar,Westerhausen, Matthias
supporting information, p. 10497 - 10500 (2013/08/23)
Reduced to the max: Halogenated polycyclic hydrocarbons can be reduced with calcium via two different pathways yielding radical anions due to electron transfer into the π*-orbital or Grignard-type reagents due to insertion of Ca into the carbon-halogen bo
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.
Tandem dienyne cross-metathesis/ring-closing metathesis
Smulik, Jason A.,Diver, Steven T.
, p. 171 - 174 (2007/10/03)
Tandem enyne cross-metathesis/ring-closing metathesis between terminal alkynes and 1,5-hexadiene has been demonstrated using the 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene-substituted ruthenium benzylidene complex. Synthesis of 2-substituted 1,3-cyclohex
A Versatile Route to 2-Substituted Cyclic 1,3-Dienes via a Copper(I)-Catalyzed Cross-Coupling Reaction of Dienyl Triflates with Grignard Reagents
Karlstroem, A. Sofia E.,Roenn, Magnus,Thorarensen, Atli,Baeckvall, Jan-E.
, p. 2517 - 2522 (2007/10/03)
A general synthesis of 2-substituted cyclic 1,3-dienes in two steps from α,β-unsaturated ketones has been developed. Formation of a dien-2-yl triflate followed by a copper(I)-catalyzed cross-coupling reaction with a Grignard reagent gives 2-substituted dienes in fair to excellent yields. Alkyl, aryl, and allyl Grignard reagents can be used.
Oxidized Phenyl-Substituted Sesquibicyclic Hydrazines
Nelsen, Stephen F.,Wang, Yichun,Hiyashi, Randy K.,Powell, Douglas R.,Neugebauer, Franz A.
, p. 2981 - 2988 (2007/10/02)
The effect of α- and β-phenyl substituents on the neutral, +1, and +2 oxidation states of bis-N,N'-bicyclic hydrazines 1 and 2 is discussed.An α-phenyl substituent on 2 makes first electron removal 1.8 kcal/mol more difficult, but second electron removal
CYCLO-CODIMERIZATION OF 1,3-BUTADIENE DERIVATIVES WITH NON-ACTIVATED TERMINAL ACETYLENES CATALYZED BY CATIONIC RHODIUM(I) COMPLEX
Matsuda, Isamu,Shibata, Masahiro,Sato, Susumu,Izumi, Yusuke
, p. 3361 - 3362 (2007/10/02)
An efficient cyclo-codimerization between 1,3-diene and non-activated terminal acetylene has been attained by the catalysis of PF6 to give 1,4-disubstituted cyclohexa-1,3-dienes under mild conditions.
