Asymmetric hydroformylation of the linear butenes by [( R,R)-Diop]Pt(SnCl 3)Cl

• Published in: Journal of organometallic chemistry Vol. 296; no. 1; pp. 281 - 290
• Main Authors: Haelg, Paul, Consiglio, Giambattista, Pino, Piero
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 01.01.1985; Elsevier Science
• Subjects: Chemical reactivity; Chemistry; Exact sciences and technology; Organic chemistry; Reactivity and mechanisms; Platinum Complexes; Catalytic reaction; Hydrocarbon; Regioselectivity; Aliphatic compound; Isomerization; Organic ligand; Asymmetric induction; Hydrogenation; Isomer; Chirality; Ditertiary phosphine; Hydroformylation; Asymmetric reaction; Ethylenic compound
• ISSN: 0022-328X; 1872-8561
• DOI: 10.1016/0022-328X(85)80355-7

The asymmetric hydroformylation of the three isomeric straight chain butenes catalyzed by [( R, R)-Diop]Pt(SnCl 3)CI (Diop is 2,2-dimethyl-4, 5-bis(diphenylphos- phinomethyl)-l,3-dioxolane) has been reinvestigated. Depending on the conditions, hydroformylation can be accompanied by extensive isomerization and hydrogenation of the substrate. Enantiomeric excess and regioselectivity depend on the extent of conversion. At least two pathways must be responsible for the formation of the straight chain aldehyde from the 2-butenes. The chirality of the 2-methylbutanal arising from 1-butene (best e.e 46.7%) is opposite to that arising from (Z)- and ( E )-2-butene. Under the conditions used asymmetric induction is determined during or before the formation of the alkyl complexes which are generally postulated as intermediates in the catalytic cycle. The assumption of the existence of different catalytic species responsible for hydroformylation and hydrogenation/isomerization accounts satisfactorily for the results.