83897-70-5Relevant academic research and scientific papers
Catalyst-controlled regioselectivity in the synthesis of branched conjugated dienes via aerobic oxidative heck reactions
Zheng, Changwu,Wang, Dian,Stahl, Shannon S.
supporting information, p. 16496 - 16499,4 (2020/09/15)
Pd-catalyzed aerobic oxidative coupling of vinylboronic acids and electronically unbiased alkyl olefins provides regioselective access to 1,3-disubstituted conjugated dienes. Catalyst-controlled regioselectivity is achieved by using 2,9-dimethylphenanthroline as a ligand. The observed regioselectivity is opposite to that observed from a traditional (nonoxidative) Heck reaction between a vinyl bromide and an alkene. DFT computational studies reveal that steric effects of the 2,9-dimethylphenanthroline ligand promote C-C bond formation at the internal position of the alkene.
A New Version of the Peterson Olefination Using Bis(trimethylsilyl)methyl Derivatives and Fluoride Ion as Catalyst
Palomo, Claudio,Aizpurua, Jesus M.,Garcia, Jesus M.,Ganboa, Inaki,Cossio, F. P.,et al.
, p. 2498 - 2503 (2007/10/02)
Reaction between a variety of bis(trimethylsilyl)methyl derivatives and carbonyl compounds under fluoride ion as catalyst is described.The reaction works especially well with nonenolizable carbonyl compounds to give the expected alkenes in high yields and, in some cases, with high stereoselectivity.Application of this methodology to an intramolecular alkenation providing a tricyclic benzocarbacephem ring system is also described.
Palladium-Catalyzed Syntheses of Aryl Polyenes
Mitsudo, Taki-aki,Fischetti, William,Heck, Richard F.
, p. 1640 - 1646 (2007/10/02)
The palladium-catalyzed arylation reaction has been employed to prepare a variety of mono- and diaryl 1,3-dienes and 1,3,5-trienes.The yields were good when electron withdrawing substituents were present in the aryl groups but only poor to fair when electron-donating groups were involved.Monoaryl dienes and trienes reacted well with all types of aryl halides to give mixed diaryl derivatives. 2-Bromostyrene reacts with phenylhexatriene to form 1,8-diphenyloctatetraene and with hexatriene to form 1,10-diphenyldecapentaene, but both only in about 15percent yield.
Wittig Reagents Bound to Cross-Linked Polystyrenes
Bernard, Margaret,Ford, Warren T.
, p. 326 - 332 (2007/10/02)
Insoluble benzyltriarylphosphonium and methyltriarylphosphonium salts have been prepared on 2percent and 8percent divinylbenzene cross-linked polystyrene and on 20percent divinylbenzene cross-linked macroporous polystyrene.Phosphoranes were generated with sodium methoxide or sodium ethoxide in THF and with the dimethylsulfinyl carbanion in Me2SO from the benzyl- and methylphosphonium salts, respectively.Reactions of the phosphoranes with a variety of aldehydes and ketones provided alkenes in 73-96percent yields (by GLC analysis) with the 2percent cross-linked polymer, 52-77percent yields with the 8percent cros s-linked polymer, and 72-87percent yields with the 20percent cross-linked macroporous polymer.The rates of phosphorane generation and alkene formation depend on the polymer, decreasing in the order 2percent > 20percent macroporous > 8percent cross-linked.The fraction of E double bond product from the benzylphosphonium salt and either benzaldehyde or cinnamaldehyde is greater with the 20percent cross-linked macroporous polymer than with the 2percent cross-linked polymer.The byproduct polymer-bound phosphine oxides were reduced to phosphines with trichlorsilane, and the phosphines were reused for Wittig synthesis.A quantitative 31P-NMR analysis of phosphine and phosphine oxide residues in polystyrene gels is reported.
