Recent Advances in Metal‐Catalyzed Asymmetric Conjugate Additions

Abstract

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Development of Conjugate Addition of Lithium Dialkylcuprates to Thiochromones: Synthesis of 2-Alkylthiochroman-4-ones and Additional Synthetic Applications

“…For example, rhodium-catalyzed conjugate addition to thiochromones only works well with arylzinc reagents to introduce aryl groups to thiochromones and it is not compatible with alkylzinc reagents or aliphatic groups in general [ 68 ]. In an effort to develop a quick entry into 2-alkylthiochroman-4-ones by taking advantage of the readily available inexpensive alkyllithium reagents and copper salts, we now report the conjugate addition of lithium dialkylcuprates [ 70 , 71 , 72 , 73 , 74 , 75 ], prepared from the corresponding inexpensive commercially available alkyllithiums, to thiochromones 1 (see Supplementary Material for the preparation of these starting materials) to afford 2-alkylthiochroman-4-ones 2 in good yields ( Figure 1 ).…”

Highly enantioselective Michael addition of α‐nitroacetate to α,β‐unsaturated pyrazolamide catalyzed by a bifunctional squaramide

“…Therefore, the development of asymmetric version of this reaction has constituted an actively pursued field, and significant progress has been achieved. [1][2][3][4] Among all documented nucleophiles, [5][6][7] α-nitroacetate [8][9][10][11] is generally utilized as masked amino acid in various organic transformations. 12,13 Moreover, α-nitroacetate also provides profound derivation after the initial reaction, such as decarboxylation [14][15][16] and denitration.…”

Enantioselective Michael Addition of Cyclic β-Diones to α,β-Unsaturated Enones Catalyzed by Quinine-Based Organocatalysts

“…The Michael addition of α,β-unsaturated compounds is an atom-economic carbon-carbon bond-forming reaction in organic synthesis, and the development of the enantioselective catalytic approach for this transformation, has attracted intensive attention [ 1 , 2 , 3 , 4 ]. Among the often-used acceptors, unactivated α,β-unsaturated enones always exhibit relatively sluggish reactivity and emerge as a class of historically challenging substrates for metal- and organocatalytic approaches [ 5 , 6 , 7 , 8 , 9 , 10 , 11 ].…”