270921-40-9Relevant academic research and scientific papers
Room-Temperature Benzylic Alkylation of Benzylic Carbonates: Improvement of Palladium Catalyst and Mechanistic Study
Kuwano, Ryoichi,Yokogi, Masashi,Sakai, Ken,Masaoka, Shigeyuki,Miura, Takashi,Won, Sungyong
, p. 1568 - 1579 (2019/09/04)
The palladium catalyst for the nucleophilic substitution of benzyl carbonates was improved by using 1,1′-bis(diisopropylphosphino)ferrocene (DiPrPF) as the ligand. The [Pd(η3-C3H5)(cod)]BF4-DiPrPF catalyst allows the benzylic substitution with soft carbanions to proceed even at 30 °C, affording the desired products in high yields (up to 99% yield). Thermally unstable pyridylmethyl esters are employable as the electrophilic substrates for the benzylic alkylation with the improved catalyst. Furthermore, we investigated the mechanism of the catalytic benzylic alkylation by means of DiPrPF ligand. The palladium(0) complex bearing DiPrPF activates the benzylic C-O bond to form the (benzyl)palladium(II) intermediate at room temperature. The coordination mode of the benzyl ligand would be equilibrium between the η1- and η3-manner. The nucleophile would preferentially react with the η3-benzyl ligand to give the desired product.
Cleavage of C–C and C–O Bonds to Form C–C Bonds: Direct Cross-Coupling between Acetylenic Alcohols and Benzylic Carbonates
Mi, Zhiyuan,Tang, Jiahao,Guan, Zhipeng,Shi, Wei,Chen, Hao
supporting information, p. 4479 - 4482 (2018/09/10)
A palladium-catalyzed cross-coupling reaction between C(sp) and C(sp3) centers was achieved in excellent yields via C–C bond cleavage and C–O bond cleavage. This procedure uses relatively stable acetylenic alcohols as reactants instead of unsta
Palladium-catalyzed benzylic substitution of benzyl carbonates with phosphorus nucleophiles
Makida, Yusuke,Usui, Kazumi,Ueno, Satoshi,Kuwano, Ryoichi
supporting information, p. 1814 - 1817 (2017/11/23)
A wide range of benzyl carbonates reacted with dimethyl phosphonate or diphenylphosphine oxide in the presence of the palladium catalyst, [Pd(η3-allyl)Cl]2DPEphos, to give dimethyl benzylphosphonates and benzyldiphenylphosphine oxides in high yields. The catalytic phosphonylation was applied to the one-pot synthesis of alkenes from the benzyl esters.
A general Pd-catalyzed α- And γ-benzylation of aldehydes for the formation of quaternary centers
Franzoni, Ivan,Guénée, Laure,Mazet, Clément
supporting information, p. 6338 - 6343 (2015/06/08)
A palladium-catalyzed benzylation of α-branched aldehydes has been developed using benzyl methyl carbonates. The method gives access to congested quaternary centers in the vicinity of one of the most sensitive carbonyl functionalities and displays unprecedented generality with respect to both coupling partners. Evidence for the direct involvement of a Pd-η3-benzyl intermediate is provided. Extension of this strategy to the γ-benzylation of α,β-unsaturated aldehydes is further demonstrated.
Radicals from fragmentation of benzyloxymethoxycarbenes in solution
Merkley, Nadine,El-Saidi, Manal,Warkentin, John
, p. 356 - 361 (2007/10/03)
2-Benzyloxy-2-methoxy-5,5-dimethyl-Δ3-1,3,4-oxadiazolines, including the parent as well as p-substituted analogues, undergo thermolysis at 100°C in benzene to afford a mixture of products. Two primary fragmentations of the oxadiazolines were identified. The major pathway involves 1,3-dipolar cycloreversion to N2 and the corresponding carbonyl ylides. The latter dissociate to acetone and the corresponding benzyloxy(methoxy)carbenes, which undergo fragmentation to ArCH2 and MeOCO radical pairs that recombine to afford methyl arylacetates. Carbene dimers were not observed, showing that the fragmentation process is faster than carbene dimerization. A second fragmentation pathway observed for the oxadiazolines is an alternative cycloreversion to the corresponding benzyl methyl carbonate and 2- diazopropane. Products from diazopropane included acetone azine and, in some instances, traces of propene.
