89012-52-2Relevant academic research and scientific papers
The synthesis and characterization of 3,3-disubstituted pent-4-enals and their 2,2-(trimethylendithio)pent-4-enal precursors, including the X-ray crystal structure of (R)-3-ethyl-3-phenyl-2,2-(trimethylenedithio)pent-4-enal
Young, Charles G.,James, Brian R.,Rettig, Steven J.
, p. 1035 - 1040 (2007/10/02)
A variety of 3,3-disubstituted pent-4-enals (5a, R=Me, R'=Et; 5b, R=Me, R'=Ph; 5c, R=Et, R'=Ph) has been prepared by the Raney nickel desulfurization of the corresponding 3,3-disubstituted 2,2-(trimethylenedithio)pent-4-enal precursors 4a-4c.The precursor compounds were prepared by the alkylation of 2-formyl-1,3-dithiane with the appropriate 3,3-disubstituted allylic bromide.The new compounds have been characterized by elemental analysis, infrared and nmr spectroscopy, and mass spectrometry.The crystal and molecular structure of (R)-4c has also been determined by X-ray crystallography.At temperatures of ca. 130 deg C, compounds 4a-4c undergo intramolecular rearrangement to form the trisubstituted alkenes 6a-6c, which have also been characterized by the present study.
CATALYTIC DECARBONYLATION, HYDROACYLATION, AND RESOLUTION OF RACEMIC PENT-4-ENALS USING CHIRAL BIS(DITERTIARY-PHOSPHINE) COMPLEXES OF RHODIUM(I)
James, Brian R.,Young, Charles G.
, p. 321 - 332 (2007/10/02)
Attempts to decarbonylate racemic aldehydes catalytically using rhodium(I) complexes containing chiral di-tertiary-phosphine ligands are described.Incorporation of an alkenic moiety into the aldehyde, for subsequent probing of induced asymmetry by chiral shift reagents, leads instead to formation of optically active hydroacylated products via kinetic resolution of the precursor racemic aldehyde.For example, (RS)-2-methyl-2-phenylpent-4-enal (1a) yields, on treatment with Cl, 2-methyl-2-phenylcyclopentanone with up to 69percent e.e of the (-)-(S) optical isomer and remaining unreacted aldehyde which is possibly the enantiomerically pure (-)-(R) form.Extension of this cyclization reaction to a 3,3-disubstituted pent-4-enal similarly provides a synthesis for an optically active 3,3-disubstituted cyclopentanone.Decarbonylation by-products are also observed; those from 1a appear as E- and Z-2-phenylpent-2-ene.The cyclization of 1a is catalyzed also by Rh(chiraphos)(solvent)2+ but with lower e.e.
