Design, synthesis and application of a new type of bifunctional Le-Phos in highly enantioselective γ-addition reactions of N-centered nucleophiles to allenoates

Abstract

A novel class of bifunctional cyclic phosphine catalysts (Le-Phos) is reported, which showed good performances in enantioselective γ-addition reactions of N-centered nucleophiles and allenoates under mild conditions.

Access to P-chiral sec- and tert-phosphine oxides enabled by Le-Phos-catalyzed asymmetric kinetic resolution

“…Encouraged by this nding, several modied chiral phosphine catalysts (S P ,R,S,R S )-Le-Phos P5-P7 with the variation of the substituent R at the center of the chiral sulnamide were then tested. 12 The enantioselectivity of 3aa could be improved to 63% along with increased yields of 3aa and recovered (R)-1a when the phosphine catalyst was switched to (S P ,R,S,R S )-Le-Phos P5 (R ¼ cyclopentyl) (Table 1, entry 5). However, isopropyl-and phenyl-substituted P6 and P7 resulted in lower enantioselectivities (Table 1, entries 6 and 7).…”

Organocatalyzed C−N bond‐forming Reactions for the Synthesis of Amines and Amides

“…The synthesized product can be easily transformed into commercially important chemical compounds (Scheme 7). [14] Seidel and co-workers recently developed a Selenourea-Thiourea based catalytic system VIII for the asymmetric additions of amines 55 to unactivated α,β-unsaturated esters 56. The resulting β-amino ester 57 having good to excellent yield and high enantiomeric excess (Scheme 8).…”

Phosphine-catalyzed divergent domino processes between γ-substituted allenoates and carbonyl-activated alkenes

“… 4 Phosphine-catalyzed annulation reactions are the most common reaction types, and various [3 + 2], 5 [4 + 1], 6 and [4 + 2] 7 annulation reactions are found to be useful for building up five- or six-membered ring systems. Moreover, phosphine-catalyzed γ-additions, 8 Michael additions, 9 Morita–Baylis–Hillman (MBH) reactions, 10 and Rauhut–Currier (RC) reactions 11 have also been shown to be synthetically useful. In our continuous pursuit of phosphine catalysis, we are particularly interested in the effective asymmetric creation of chiral scaffolds of biological significance.…”