Abstract An efficient water-based bismuth-mediated addition reaction of carbonyl compound with cyclic allylic halide was developed. The reactions proceeded smoothly in aqueous DMF in the presence of ammonium iodide to afford the corresponding syn -homoallylic alcohols in moderate to good yields with excellent diastereoselectivities (>99:1 syn : anti ). Reversal of product diastereoselectivity was observed
homoallylic alcohols in good to excellent yields with high diastereoselectivities (>99:1 dr). Reversed diastereoselectivity was obtained when carbonylsubstrate (e. g., 2‐pyridinecarboxaldehyde, glyoxylic acid) containing chelating substituent was used in the allylation reaction. In addition, the reactions involving acyclic (E)‐cinnamyl bromide as substrate worked equally well with high diastereocontrol.
Diethylzinc‐Mediated Allylation of Carbonyl Compounds Catalyzed by [(NHC)(PR
<sub>3</sub>
)PdX
<sub>2</sub>
] and [(NHC)Pd(η
<sup>3</sup>
‐allyl)Cl] Complexes
作者:Alexandre Flahaut、Krimo Toutah、Pierre Mangeney、Sylvain Roland
DOI:10.1002/ejic.200900891
日期:2009.12
reaction was investigated with this complex. [(IMesMe)(PPh3)PdI2] catalyzes the allylation of aromatic (except 4-nitrobenzaldehyde) and aliphatic aldehydes (including enolizable aldehydes) with cinnamyl acetate to give the corresponding homoallylic alcohols in 57–98 % yields and diastereoselectivities ranging from 70:30 to 92:8. The allylation of acetone also takes place under the same conditions, leading
Asymmetric allylation of aryl aldehydes: studies on the scope and mechanism of the palladium catalysed diethylzinc mediated umpolung using phosphoramidite ligands
作者:Gareth P. Howell、Adriaan J. Minnaard、Ben L. Feringa
DOI:10.1039/b518165h
日期:——
Using modular, monodentate phosphoramidite ligands, enantioselective palladium catalysed diethylzinc mediated allylation of aldehydes was achieved. The scope of the asymmetric C–C bond formation was investigated with respect to nucleophilic and electrophilic components and an alternative reaction mechanism is proposed based on our findings.
BuSnCl<sub>3</sub>-Mediated Reaction of 3-(Tributylstannyl)cycloalkenes with Aldehydes. Highly<i>erythro</i>-Selective 2-Cyclopentenylation and 2-Cyclohexenylation of Aromatic Aldehydes
作者:Hideyoshi Miyake、Kimiaki Yamamura
DOI:10.1246/cl.1992.2221
日期:1992.11
3-(Butyldichlorostannyl)cyclopentene and 3-(butyldichlorostannyl)cyclohexene, which are prepared by the transmetalation of corresponding 3-(tributylstannyl)cycloalkene with BuSnCl3, react with aromatic aldehydes to give 2-cycloalkenylated products with excellent erythro-selectivity. However, the corresponding reaction with aliphatic aldehydes proceeded in only moderate erythro-selectivity.