One-pot β-substitution of enones with alkyl groups to β-alkyl enones

Abstract

Vinylic hydrogens at the beta-position of enones were effectively substituted with alkyl groups in a one-pot procedure to afford beta-alkyl enones in good to high isolated yields by conjugate addition of higher-order dialkyl cyanocuprates to enones, followed by a reaction with N-tert-butylbenzenesulfinimidoyl chloride at -78 degree C.

Palladium-Catalyzed Oxidative Rearrangement of Tertiary Allylic Alcohols to Enones with Oxygen in Aqueous Solvent

“…1H NMR (400 MHz, CDCl3) δ 5.87 (d, J = 0.5 Hz, 1H), 2.37 (dd, J = 7.6, 5.8 Hz, 2H), 2.26 (ddd, J = 5.4, 4.9, 1.3 Hz, 2H), 2.20 (dd, J = 13.9, 6.9 Hz, 1H), 2.02 -1.94 (m, 2H), 1.47 (ddt, J = 21.3, 14.4, 7.3 Hz, 2H), 1.08 (d, J = 6.9 Hz, 3H), 0.85 (t, J = 7.4 Hz, 3H). 13 3-(tert-butyl)cyclohex-2-en-1-one (3c) 16 : Colorless oil (140 mg, 92%). Rf = 0.42 (hexane / EtOAc = 6 / 1).…”

“…1 H NMR (400 MHz, CDCl 3 ) δ 7.48 -7.35 (m, 5H), 6.31 (s, 1H), 2.92 -2.84 (m, 2H), 2.72 -2.63 (m, 2H), 1.99 -1.85 (m, 4H). 13 3-Butylcyclohept-2-en-1-one (3p) 16 : Colorless oil (133mg, 80%), with 10% (17 mg) of 1p recovered. Rf = 0.45 (hexane / EtOAc = 6 / 1).…”

Highly efficient methods for the one-pot synthesis of β-substituted enones

“…However, following completion of our studies and during the preparation of our manuscript for publication, Matsuo and Aizawa divulged their findings using a very similar approach. 10 Based on this, we now communicate the preparative outcomes from our endeavours in this area, whilst highlighting the differences and potentially wider practical utility of our techniques over the recently published procedures.…”

“…1; 27% yield). 10 Following these successful initial optimisation studies, the generality and applicability of our developed method with alternative a,b-unsaturated substrates was investigated using a Gilman cuprate. † As Table 2 illustrates, this technique provides good to excellent yields of b-substituted enones from all of the unsaturated starting materials employed.…”

“…In contrast and to complement the methods reported here, this previously published study shows how higher order dialkyl (or diaryl) cyanocuprates can be employed successfully in this addition-oxidation process, albeit with excesses of the transferring unit being required. 10 In summary, we have developed a mild and practicallyconvenient one-pot conjugate addition-oxidation protocol, to directly produce b-substituted enones in a highly efficient manner. This methodology has proven to be effective with both cyclic and acyclic enones.…”