Enantioselective Copper‐Catalyzed Conjugate Addition of Trimethylaluminum to β,γ‐Unsaturated α‐Ketoamides: Efficient Access to γ‐Methyl‐Substituted Carbonyl Compounds

Abstract

Picture perfect: By using the reagent trimethylaluminium and β,γ-unsaturated α-ketoamides, 1,4-adducts were obtained with perfect 1,4-regioselectivity and good to excellent yields and ee values. The potential synthetic utility of the methodology was highlighted by preparation of γ-methyl-substituted carbonyls, key synthons to many natural products. binap=2,2′-bis(diphenylphosphino)-1,1′-binaphthyl, TC=thiophene carboxylate

Copper‐Catalyzed Asymmetric Conjugate Addition of Dimethylzinc to Acyl‐N‐methylimidazole Michael Acceptors: a Powerful Synthetic Platform

“…[5] Nevertheless,t he enantioselective transfer of amethyl group to form all-carbon methylsubstituted chiral scaffolds,w hich are present in numerous natural products, [5] remains achallenge. [6] On the other hand, the electron-withdrawing group (EWG) of Michael acceptors has to be considered not only as aplatform for postfunctionalization but should also be compatible with the methylated organometallic reagents and allow its enantioselective addition. To this end, thioesters have been successfully used with the methyl-Grignard nucleophile,a llowing notably iterative ECAp rocesses to form 1,3-desoxypropionate subunits.…”

Bi(OAc)3/Chiral Phosphoric Acid-Catalyzed Enantioselective 1,2- and Formal 1,4-Allylation Reaction of β,γ-Unsaturated α-Ketoesters

“…However, the asymmetric allylation reaction of β,γ-unsaturated α-ketoesters has been rarely reported. Meanwhile, both 1,2- and 1,4-allylation products are significant chiral derivatives used to synthesize natural products and pharmaceuticals (Figure a) . Therefore, it is very meaningful and challenging to find a specific asymmetric allylation method of β,γ-unsaturated α-ketoesters that can control 1,2- or 1,4-allylation.…”

Catalytic Asymmetric Conjugate Addition of a Borylalkyl Copper Complex for Chiral Organoboronate Synthesis

“…The catalytic asymmetric conjugate addition of organometallic reagents to a,b-unsaturated compounds is one of the key methods for C À Cb ond formation with the efficient construction of new carbon stereogenic centers. [1] In the past decades,a ir-sensitive nonstabilized organometallic nucleophiles,s uch as Grignard reagents, [2] organozinc reagents, [3] organoaluminum reagents, [4] and organozirconium reagents, [5] have been used. However,the use of stoichiometric amounts of these reagents and difficulties in handling them generally limited their synthetic efficiency.…”