1,3-Diketones were synthesized from alpha,beta-unsaturated ketones by treatment with acid chlorides and Et(2)Zn in the presence of RhCl(PPh(3))3. This is a very simple and extremely chemoselective reaction to give the adduct at the alpha-position of alpha,beta-unsaturated ketones.
The reaction of tris(triphenylphosphine)-with diethylzinc (Et 2 Zn) easily afforded a rhodium-hydride complex that effects the 1,4-reduction of a,b-unsaturated esters to give rhodium enolates. Formation of the rhodium enolate is followed by transmetalation with the zinc species to give a Reformatsky-type reagent, and this reacts with various acid chlorides at the aposition to give b-keto esters. The Reformatsky-type reagent also reacts with various electrophiles such as aldehydes, ketones and acid anhydrides to give the corresponding products in which the electrophiles were introduced reductively at the a-position of a,bunsaturated esters.
Ketones Q 0350Direct Synthesis of 1,3-Diketones by Rh-Catalyzed Reductive α-Acylation of Enones. -A very simple and extremely chemoselective synthesis of 1,3-diketones is developed and applied to the one-pot synthesis of a pyrazole (VI). -(SATO, K.; YAMAZOE, S.; YAMAMOTO, R.; OHATA, S.; TARUI, A.; OMOTE, M.; KUMADAKI, I.; ANDO*, A.; Org. Lett. 10 (2008) 12, 2405-2408; Fac. Pharm. Sci., Setsunan Univ., Hirakata, Osaka 573-01, Japan; Eng.) -R. Steudel 45-087
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.