Switching Diastereoselectivity in Catalytic Enantioselective (3+2) Cycloadditions of Azomethine Ylides Promoted by Metal Salts and Privileged Segphos-Derived Ligands

Abstract

Catalytic enantioselective 1,3-dipolar cycloaddition between imino esters and electrophilic alkenes, employing chiral metal complexes derived from copper(I) and silver(I) salts and (S)-DM-or (S)-DTBM-Segphos as ligands produces diastereodivergently exo-or endo-cycloadducts, respectively. The effect of the functional group of the dipolarophile and the fine tuning of the catalyst plays an important role in promoting reverse diastereoselectivities. The origins of experimentally observed enantioselectivity and diastereoselectivity data, as well as the origin of the observed switched endo/exo ratios, are also explained by means of density functional theory calculations.

FAM‐Ag‐catalyzed asymmetric synthesis of heteroaryl‐substituted pyrrolidines

“…In another study, a Ag‐hydrocinchonine chiral catalyst was reported by Alemparte et al 7 for the enantioselective synthesis of a 2‐furyl‐substituted pyrrolidine derivative also as the only heteroaryl‐substituent. Synthesis of 2‐thienyl‐ and 3‐pyridiyl‐substituted pyrrolidine derivatives were seen in the previous studies using Ag‐BINAP and Ag‐phosphoramidate chiral catalysts 8–11 . Kim et al 12 and Li et al 13 reported enantioselective synthesis of 2‐thienyl‐ and 2‐furyl‐susbstituted pyrrolidines by using Ag‐ and Cu‐Brucinediol chiral catalysts.…”

“…Synthesis of 2-thienyl-and 3-pyridiyl-substituted pyrrolidine derivatives were seen in the previous studies using Ag-BINAP and Agphosphoramidate chiral catalysts. [8][9][10][11] Kim et al 12 and Li et al 13 reported enantioselective synthesis of 2-thienyland 2-furyl-susbstituted pyrrolidines by using Ag-and Cu-Brucinediol chiral catalysts. Another example is the study of Han et al, 14 where Cu-Ferrocenyl P,S chiral catalyst was used for the enantioselective synthesis of 2-thienyl-substituted pyrrolidine.…”

“…(2S, 4S, 5R)-Dimethyl 5-(furan-2-yl) pyrrolidine-2,4-dicarboxylate (10d)11 Using the general procedure, cycloadduct 10d was obtained in 79% yield as a light yellow solid.1 H NMR (400 MHz, CDCl 3 ) δ 7.31 (dd, J = 1.7, 0.7 Hz, 1H), 6.28 (dd, J = 3.2, 1.8 Hz, 1H), 6.26 (d, J = 3.2 Hz, 1H), 4.57 (d, J = 7.4 Hz, 1H), 3.95 (t, J = 8.2 Hz, 1H), 3.78 (s, 3H), 3.46 (s, 3H), 3.28 (q, J = 7.4 Hz, 1H), 3.09 (br, 1H), 2.49-2.35 (m, 2H). 13 C NMR (100 MHz, CDCl 3 ) δ 173.8, 172.4, 152.7, 142.1, 110.3, 107.2, 59.4 (2 Â C), 52.4, 51.8, 48.4, 32.3.…”

Vibrational Circular Dichroism for the Assignment of Absolute Configuration of Natural Products in Brazil

“…In this section, we will present a list of natural products and related compounds studied by Brazilian researchers (Table S1), which had their absolute configuration assigned using VCD spectroscopy and DFT calculations, associated or not with other techniques (Batista Jr et al 2011b;2013;2015b;Batista et al 2019;Caldas et al 2020;Caleffi et al 2019;Canzi et al 2018;Covington et al 2016;Demarque and Merten 2017;Felippe et al 2012;Gimenes et al 2019;Joseph-Nathan et al 2010;Lianza et al 2020;Londero et al 2021;Medina et al 2019;Morais et al 2020;Ortega et al 2017;Ortega et al 2018;Ortega et al 2019;Queiroz et al 2019;Rodriguez et al 2020;Santos Jr et al 2014;Scatena et al 2017;Socolsky et al 2012;Souza et al 2019;Teodoro et al, 2018a;2018b). Some selected examples will be discussed in detail below.…”

The Crucial Role of S‐oxidation State on the Selectivity and Reaction Rate of the 1,3‐Dipolar Cycloaddition of Azomethine Ylides and Homochiral Thiazolines

“…[1,2] A vast number of publications have been published since several years ago dealing with the insights of this cycloaddition due to the versatile organic molecules obtained through this methodology. [3][4][5][6][7][8][9][10][11][12] More interesting is the asymmetric version of this reaction, which allows to obtain up to 4 stereogenic centers in one reaction step in a selective manner, classically achieved by the use of metal-or organocatalysis. [13][14][15][16][17][18][19][20][21] The origin of the exo/endo selectivity in the catalytic asymmetric synthesis of pyrrolidines by 1,3-dipolar cycloaddition of azomethine ylides has been brilliantly rationalized and reported recently.…”