The Vespiary

The Hive => Novel Discourse => Topic started by: Rhodium on January 19, 2002, 02:32:00 PM

Title: New ways to Phenyl-2-propanone
Post by: Rhodium on January 19, 2002, 02:32:00 PM

Two new ways to P2P, starting with bromobenzene

[Bull Soc Chem Jap 57, 242 (1984)]

To a stirred solution of an aryl bromide (60 mmol), isopropenyl acetate (9g, 90 mmol) and dichlorobis(tri-o-tolylphosphine)palladium (0.47g, 0.67 mmol) in dry toluene (30 ml), under nitrogen, was added tributyltin methoxide (25.9 ml, 90 mmol; Aldrich). The mixture was stirred and heated at 100 deg C for 5 hr, cooled and the solvent evaporated in vacuo. The residue was chromatographed on silica gel, to afford the aryl-2-propanone in 67% yield.


[Chem Lett 597 (1982)]

To a stirred solution of an aryl bromide (53.9 g, 200 mmol) in DMF (1 liter) was added cuprous iodide (32.4 g, 167 mmol) and potassium acetylacetonate hemihydrate (125g, 834 mmol; Aldrich). The mixture was stirred and heated at 100 deg C for 24 hr, cooled, stirred with 2M sodium hydroxide (250 ml)  for 1 hr and extracted with toluene (2x500 ml). The combined extracts were washed with water, 1M hydrochloric acid and satd. aq. sodium bicarbonate, dried over magnesium sulphate and concentrated in vacuo to leave a dark brown oil, which after purification gave the aryl-2-propanone in 65% yield.

Title: P2P by Pd-catalyzed arylation of acetone enolether
Post by: Rhodium on October 05, 2004, 08:06:00 PM

Arylation and 1-Alkenylation on ?-Position of Ketones via Tributyltin Enolates Catalyzed by Palladium Complex
Masanori Kosugi, Isao Hagiwara, Takao Sumiya. and Toshihiko Migita

Bull. Chem. Soc. Jpn. 57, 242-246 (1984) (https://www.thevespiary.org/rhodium/Rhodium/pdf/arylation.isopropenylacetate.pd-busnome.pdf)

(https://www.thevespiary.org/rhodium/Rhodium/pdf/arylation.isopropenylacetate.pd-busnome.pdf)

Abstract
The reaction of tributyltin enolates, prepared from tributyltin methoxide and enol acetates in situ, with aryl and 1-alkenyl bromides in the presence of dichlorobis(tri-o-tolylphosphine)palladium was found to give ?-aryl and ?-(1-alkenyl)ketones, respectively, in good yields with essentially complete retention of the enol acetate regiochemistry.