33867-02-6Relevant academic research and scientific papers
Congested C-C bonds by Pd-catalyzed enantioselective allyl-allyl cross-coupling, a mechanism-guided solution
Ardolino, Michael J.,Morken, James P.
, p. 7092 - 7100 (2014/06/09)
Under the influence of a chiral bidentate diphosphine ligand, the Pd-catalyzed asymmetric cross-coupling of allylboron reagents and allylic electrophiles establishes 1,5-dienes with adjacent stereocenters in high regio-and stereoselectivity. A mechanistic study of the coupling utilizing reaction calorimetry and density functional theory analysis suggests that the reaction operates through an inner-sphere 3,3′-reductive elimination pathway, which is both rate-defining and stereodefining. Coupled with optimized reaction conditions, this mechanistic detail is used to expand the scope of allyl-allyl couplings to allow the generation of 1,5-dienes with tertiary centers adjacent to quaternary centers as well as a unique set of cyclic structures.
Palladium-catalyzed regio- and enantioselective fluorination of acyclic allylic halides
Katcher, Matthew H.,Sha, Allen,Doyle, Abigail G.
supporting information; experimental part, p. 15902 - 15905 (2011/11/13)
This report describes the Pd(0)-catalyzed fluorination of linear allylic chlorides and bromides, yielding branched allylic fluorides in high selectivity. Many of the significant synthetic limitations previously associated with the preparation of these products are overcome by this catalytic method. We also demonstrate that a chiral bisphosphine-ligated palladium catalyst enables highly enantioselective access to a class of branched allylic fluorides that can be readily diversified to valuable fluorinated products.
Synthesis and comparative antibacterial activity of verdamicin C2 and C2a. A new oxidation of primary allylic azides in dihydro[2H]pyrans
Hanessian, Stephen,Szychowski, Janek,Pablo Maianti
supporting information; experimental part, p. 429 - 432 (2009/09/25)
(Chemical Equation Presented) A synthesis of verdamicin C2 and its congener C2a has been accomplished from sisomicin relying on a novel oxidative transformation of an allylic azide to the corresponding α,β- unsaturated aldehyde, and its stereocontrolled elaboration into the intended 5′ side chain of verdamicin C2 and C2a. In vitro antibacterial testing shows that both C6′ epimers in verdamicin C2 and C2a are equally active against a variety of bacterial strains. Oxidation of allylic primary azides, ethers, and esters of 2-substituted dihydro[2H]pyrans with SeO2 leads directly to the corresponding aldehydes.
β- and γ-disubstituted olefins: Substrates for copper-catalyzed asymmetric allylic substitution
Falciola, Caroline A.,Tissot-Croset, Karine,Reyneri, Hugo,Alexakis, Alexandre
supporting information; experimental part, p. 1090 - 1100 (2009/05/30)
The copper-catalyzed asymmetric allylic alkylation has shown through many examples that it is a powerful means to generate stereogenic centers with mono β- and γ-substituted olefinic substrates. However, little has been reported about more substituted olefinic patterns, such as β-disubstituted allylic electrophiles. In this paper, we show that a simple procedure using easily accessible Grignard reagents and as low as 3 mol% of copper/ligand can promote high to nearly perfect enantioselectivities (up to >99% ee) with very good γ-selectivities on a wide panel of aliphatic or aromatic β-disubstituted substrates.
Regio- and stereospecific formation of protected allylic alcohols via zirconium-mediated SN2′ substitution of allylic chlorides
Fox, Richard J.,Lalic, Gojko,Bergman, Robert G.
, p. 14144 - 14145 (2008/09/18)
A new, highly regio- and stereospecific SN2′ substitution reaction between a zirconium oxo complex and allylic chloride has been achieved. The resulting allylic alcohol or TBS-protected allylic ether products were isolated in good to excellent yields with a wide range of E-allylic chlorides. A mechanism for the SN2′ allylic substitution consistent with kinetic, stereochemical, and secondary isotope effect studies was proposed. Copyright
Initiated tert-Butyl Hydroperoxide-loaded Low-temperature Autoxidation of Alkenes: Alternative Hydroperoxide Syntheses and the Preparation of a Complete Set of Reference Material
Courtneidge, John L.,Bush, Melanie,Loh, Lay-See
, p. 1539 - 1548 (2007/10/02)
A complete set of characterization data for the allylic hydroperoxides prepared from 1-methylcyclohexene and the isomeric 4-methyloct-4-enes is presented.The data relies upon the preparation of allylic hydroperoxides by tert-butyl hydroperoxide-loaded autoxidations, singlet-ene oxidations and nucleophilic substitution reactions.Appropriate allylic alcohols and relevant scission products have been prepared to support the assignments given.
A short and efficient synthesis of grisan
Kaufman,Sindelar
, p. 879 - 881 (2007/10/02)
A three-step synthesis of grisan (spiro[benzofuran-2(3H)-1'-cyclohexane]), using methoxymethoxybenzene and 1-chloromethylcyclohexane as starting materials, is described.
Hydroxylation by Cytochrome P-450 and Metalloporphyrin Models. Evidence for Allylic Rearrangement
Groves, John T.,Subramanian, Durga V.
, p. 2177 - 2181 (2007/10/02)
The allylic hydroxylation of 3,3,6,6-tetradeuteriocyclohexene, methylenecyclohexane, and β-pinene has been examined with phenobarbital-induced liver microsomal cytochrome P-450 (P-450LM2) and with iron porphyrin and chromium porphyrin model systems.Aerobic and peroxide dependent enzymic regimes were investigated with purified P-450LM2 and with microsomal suspensions.Epoxidation and allylic hydroxylation were primary reactions with all substrates.With 3,3,6,6-tetradeuteriocyclohexene, the major hydroxylation product (60-80percent) was the result of hydroxylation at the deuterated allylic site.In all cases, a significant amount (20-40percent) of hydroxylation occurred with allylic rearrangement.The iron porphyrin/iodosylbenzene model system also showed preferential hydroxylation of the deuterated allylic site (70percent) with significant allylic rearrangement (30percent).By contrast, the chromium porphyrin/iodosylbenzene model system showed complete scrambling of the allylic system.Extensive rearrangement accompanied the hydroxylation of methylenecyclohexane and β-pinene by both the enzymic and metalloporphyrin systems whereas the selenium dioxide oxidation of these substrates gave selective allylic hydroxylation without rearrangement.A mechanism is suggested for allylic hydroxylation by cytochrome P-450 and by the metalloporhyrin model systems involving initial hydrogen atom abstraction from the allylic site and geminate, cage recombination of the incipient, allylic free radical.
Regiospecific addition of benzeneselenenyl halide to 1,1-disubstituted olefins
Ho, Pak-Tsun,Kolt, Ralph J.
, p. 663 - 666 (2007/10/02)
The reaction of benzeneselenenyl halide with a variety of 1,1-disubstituted olefins under controlled conditions yields regiospecifically the anti-Markovnikov adducts which have been converted into the synthetically yseful vinyl halides and allyl halides.
THE REACTION OF HYPOCHLOROUS ACID WITH OLEFINS. A CONVENIENT SYNTHESYS OF ALLYLIC CHLORIDES
Hegde, Shridhar G.,Vogel, Martin K.,Saddler, John,Hrinyo, Tanya,Rockwell, Ned,et al.
, p. 441 - 444 (2007/10/02)
The reaction of HOCl with more highly substituted olefins in methylene chloride affords allylic chlorides in 60-80percent isolated yields.The utility of the reaction is illustrated with the synthesis of Rose oxide and α-monoterpenes.
