Harnessing Electron Donor-Acceptor Complexes to Improve the Sustainability of the Enantioselective β-Alkylation of Aromatic Enals.

A novel and sustainable method is presented for the enantioselective β-alkylation of enals using an electron donor-acceptor (EDA) complex-based strategy. β-Alkyl-γ-azo aldehydes, important intermediates in the synthesis of bioactive compounds, are typically synthesized using organocatalysis, rhodium-catalyzed hydroformylations, or radical additions. Existing photoredox radical approaches-particularly those relying on iminium ion excitation-display severe limitations, particularly related to overall catalytic sustainability.

Diastereoselective Synthesis of Silyl-Substituted Pyrrolidines.

In this paper, we report the synthesis and structural investigation of enantioenriched methylene isosteres of Hayashi-Jørgensen catalysts, and their application in organocatalysis. -protected pyrrolidines - were prepared in high yields and excellent diastereoselectivity using a new one-pot, four-step synthetic protocol involving: (a) the formation of a silyllithium reagent (), (b) its addition to a diaryl olefin () to generate a silyl-substituted diphenylethyllithium intermediate (), (c) the highly diastereoselective addition of this intermediate to a chiral sulfinimine (), and (d) intramolecular cyclization to the desired products. After -deprotection, the new catalysts were further evaluated in benchmark Michael additions of aliphatic aldehydes to β-nitrostyrene, under various conditions, demonstrating reactivity and stereoselectivity comparable to the Hayashi catalyst.