22859-80-9Relevant articles and documents
Tandem Acid/Pd-Catalyzed Reductive Rearrangement of Glycol Derivatives
Ciszek, Benjamin,Fleischer, Ivana,Kathe, Prasad,Schmidt, Tanno A.
, p. 3641 - 3646 (2020/03/25)
Herein, we describe the acid/Pd-tandem-catalyzed transformation of glycol derivatives into terminal formic esters. Mechanistic investigations show that the substrate undergoes rearrangement to an aldehyde under [1,2] hydrogen migration and cleavage of an oxygen-based leaving group. The leaving group is trapped as its formic ester, and the aldehyde is reduced and subsequently esterified to a formate. Whereas the rearrangement to the aldehyde is catalyzed by sulfonic acids, the reduction step requires a unique catalyst system comprising a PdII or Pd0 precursor in loadings as low as 0.75 mol % and α,α′-bis(di-tert-butylphosphino)-o-xylene as ligand. The reduction step makes use of formic acid as an easy-to-handle transfer reductant. The substrate scope of the transformation encompasses both aromatic and aliphatic substrates and a variety of leaving groups.
Catalytic C-H Arylation of Aliphatic Aldehydes Enabled by a Transient Ligand
Yang, Ke,Li, Qun,Liu, Yongbing,Li, Guigen,Ge, Haibo
supporting information, p. 12775 - 12778 (2016/10/13)
The direct arylation of aliphatic aldehydes has been established via Pd-catalyzed sp3 C-H bond functionalization in the presence of 3-aminopropanoic acids as transient directing groups. The reaction showed excellent functional group compatibility and chemoselectivity in which a predominant preference for functionalizing unactivated β-C-H bonds of methyl groups over others was achieved. In addition, C-H bonds of unactivated secondary sp3 carbons can also be functionalized. The extreme popularity and importance of aliphatic aldehydes would result in broad applications of this novel method in organic chemistry and medicinal sciences.
SuperQuat N-acyl-5,5-dimethyloxazolidin-2-ones for the asymmetric synthesis of α-alkyl and β-alkyl aldehydes
Bull, Steven D.,Davies, Stephen G.,Nicholson, Rebecca L.,Sanganee, Hitesh J.,Smith, Andrew D.
, p. 2886 - 2899 (2007/10/03)
The proclivity of α-branched N-2′-benzyl-3′-phenylpropionyl derivatives of (S)-4-benzyl-5,5-dimethyl-, (S)-4-phenyl-5,5-dimethyl-, (S)-4-isopropyl-5,5-dimethyl-, (S)-4-benzyl- and (S)-4-benzyl-5,5-diphenyl-oxazolidin-2-ones to generate directly 2-benzyl-3-phenylpropionaldehyde upon hydride reduction with DIBAL is investigated. The (S)-4-benzyl-5,5-dimethyl-derivative proved optimal for inhibition of endocyclic nucleophilic attack, giving 2-benzyl-3-phenylpropionaldehyde in good yield upon reduction. Application of this methodology for the asymmetric synthesis of chiral aldehydes via diastereoselective enolate alkylation of a range of (S)-N-acyl-4-benzyl-5,5-dimethyloxazolidin-2-ones to afford an array of α-substituted-N-acyl-5,5-dimethyloxazolidin-2-ones (85-94% de) and subsequent reduction with DIBAL afforded directly non-racemic α-substituted aldehydes without loss of stereochemical integrity (87-94% ee). The extension of this protocol for the asymmetric synthesis of β-substituted aldehydes is demonstrated, via the diastereoselective conjugate addition of a range of organocuprates to (S)-N-acyl-4-phenyl-5,5-dimethyloxazolidin-2-ones which proceeds with high diastereoselectivity (generally >95% de). Reduction of the conjugate addition products with DIBAL gives non-racemic β-substituted aldehydes in high yields and in high ee (generally >95% ee). This methodology is exemplified by the asymmetric synthesis of (R)-3-isopropenylhept-6-enal, which has previously been used in the synthesis of (3Z,6R)-3-methyl-6-isopropenyl-3,9-decadien-1-yl acetate, a component of the sex pheromones of the California red scale.
SuperQuat, (S)-4-benzyl-5,5-dimethyl-oxazolidin-2-one for the asymmetric synthesis of α-substituted-aldehydes
Bull, Steven D.,Davies, Stephen G.,Nicholson, Rebecca L.,Sanganee, Hitesh J.,Smith, Andrew D.
, p. 3475 - 3479 (2007/10/03)
Reduction of α-substituted-(S)-N-acyl-4-benzyl-5,5-dimethyl-oxazolidin-2-ones with DIBAL-H in CH2Cl2 affords α-substituted aldehydes with no loss of stereochemical integrity at their α-centre. Copyright (C) 2000 Elsevier Science Ltd.
A New Synthetic Application of 1,2-Benzodithiolium Cations: Synthesis of Aldehydes by 1-Carbon Homologation of Carbonyl Compounds
Ceruti, Maurizio,Degani, Iacopo,Fochi, Rita
, p. 79 - 82 (2007/10/02)
Eleven aldehydes (6a-l) were synthesized by 1-carbon homologation of ketones and aldehydes according to the following sequence: Horner-Emmons reaction of 2-(O,O-dimethylphosphonyl)-1,3-benzodithiole (1) and various carbonyl compounds (2) to give benzo-1,4-dithiafulvenes (3); reduction with sodium borohydride and tetrafluoroboric acid-ether complex in dry acetonitrile to 1,3-benzodithioles (5); subsequent hydrolysis of these with mercury(II)oxide and aqueous tetrafluoroboric acid (35percent) in tetrahydrofuran.The procedure is simple, of wide application, and afforded pure aldehydes in good overall yields (55-88percent).
