Design and synthesis of a tridentate ligand for asymmetric bifunctional catalysis

Bifunctional organo/metal cooperative catalysis with cinchona alkaloid scaffolds

“…Lin and co-workers studied the enantioselective addition of diethyl zinc (73) to various aromatic aldehydes 72 with cinchonaderived ligand 74 as reported in Scheme 20. 43 Good enantioselectivies of up to 93% ee were achieved on six substrates. The proposed active catalyst 76 consists of both a Lewis acidic metal and a Brønsted base within the same molecule and can be synthesized in two steps from commercially available starting materials (Fig.…”

Cinchona Alkaloids and their Derivatives as Chirality Inducers in Metal‐Promoted Enantioselective Carbon–Carbon and Carbon–Heteroatom Bond Forming Reactions

“…The catalytically active zinc complex 2 can be generated in situ from the ligand 1 during the addition of diethylzinc to aldehydes [6]. The reaction of diethylzinc with 2-methoxybenzaldehyde using 10 mol% of 1 was completed within 3 h at room temperature, affording the desired (S)-carbinol in 94% yield with 92% ee (Table 4.2, entry 1).…”