A Cu^II‐N,P Oxazolinylferrocene Ligand Complex for the Asymmetric [3+2] 1,3‐Dipolar Cycloaddition of Azomethine Ylide with Malonates

Abstract

A series of enantioselective pyrrolidine‐2,4,4‐tricarboxylate derivatives were synthesized by the [3+2] 1,3‐dipolar cycloaddition of azomethine ylide with alkylidene malonates. By using 4 mol % of a CuIIN,P oxazolinylferrocene ligand complex and 10 mol % of a base, pyrrolidine analogues were obtained in high yields (77–99 %) and excellent enantioselectivities (up to 99 % ee).

Microwave-promoted, catalyst-free, multi-component reaction of proline, aldehyde, 1,3-diketone: one pot synthesis of pyrrolizidines and pyrrolizinones

“…15 This known intermediate 13 then undergoes decarboxylation to form the azomethine ylide 14. The resulting ylide 14 and its resonance contributing form 15 can further react with 2-benzylidene-1H-indene-1,3(2H)-dione 3a via the [3+2] cycloaddition 16 to give the products 4a and 5a, respectively. Scheme 3.…”

Chiral Oxazolinyl Hydroxyl Ferrocene Catalysts: Synthesis and Applications in Asymmetric Reactions

“…Guiry synthesized gem ‐disubstituted N , O ‐ferrocenes ( Sp )‐ 5 and ( Rp )‐ 5 . Very recently, motivated by our previous work, we successfully prepared a range of N , O ‐ferrocenes, 6 , containing silyl ethers . Bolm presented an example of an alternative hydroxyl moiety.…”

Asymmetric Construction of Pyrrolidines Bearing a Trifluoromethylated Quaternary Stereogenic Center via CuI‐Catalyzed 1,3‐Dipolar Cycloaddition of Azomethine Ylides with β‐CF3‐β,β‐Disubstituted Nitroalkenes

“…Recently,w er eported an ew siloxane-substituted FOXAP ligand (Si-FOXAP, L1), which exhibited high diastereoselectivity and enantioselectivity in the Cu II -catalyzed asymmetric1 ,3-dipolar cycloaddition of azomethine ylides with alkylidene malonates. [16] Encouraged by this achievement, we startedo ur work on the preparation of pyrrolidinesb earing aq uaternary stereocenter at the C-3 position. Initially, we chose b-CF 3 -b,b-disubstituted nitroalkenesa st he dipolarophiles in the 1,3-dipolarc ycloaddition.…”