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
Indium-Mediated, Highly Efficient and Diastereoselective Addition of Cyclic Secondary Allylic Bromides to Carbonyl Compounds
作者:Faiz Ahmed Khan、B. Prabhudas
DOI:10.1016/s0040-4020(00)00672-4
日期:2000.9
Indium-mediated addition of 3-bromocyclohexene and 3-bromocyclooctene to a variety of aromatic aldehydes and cyclohexanone proceeds smoothly with excellent syn diastereoselectivity to produce the corresponding cycloalkenyl substituted homoallylic alcohols in good to high yields.
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.
作者:Benjamin M. Partridge、Francesca M. Dennis、Craig C. Robertson
DOI:10.1055/s-0039-1690091
日期:2020.7
A nickel catalyst for the allylboration of aldehydes is reported, facilitating the preparation of homoallylic alcohols in high diastereoselectivity. The observed diastereoselectivities and NMR experiments suggest that allylation occurs through a well-defined six-membered transition state, with nickel acting as a Lewis acid.
Catalytic asymmetric allylation of aldehydes with alkenes through allylic C(sp<sup>3</sup>)–H functionalization mediated by organophotoredox and chiral chromium hybrid catalysis
describe a hybrid system that realizes cooperativity between an organophotoredox acridinium catalyst and a chiral chromium complex catalyst, thereby enabling unprecedented exploitation of unactivated hydrocarbon alkenes as precursors to chiral allylchromium nucleophiles for asymmetricallylation of aldehydes. The reaction proceeds under visible light irradiation at room temperature, affording the corresponding