Enantioselective Ring Opening of meso-Epoxides by Aromatic Amines Catalyzed by Lanthanide Iodo Binaphtholates

Abstract

[reaction: see text] Lanthanide iodo binaphtholates are efficient enantioselective catalysts for the ring opening of meso-epoxides by various aromatic amines. The study of the influence of temperature on the ring opening of cyclohexene oxide by o-anisidine catalyzed by the samarium complex shows an isoinversion effect with the maximum enantiomeric excess at -40 degrees C. Reactions of aniline, o-anisidine, or p-anisidine with five- or six-membered ring epoxides at this temperature allow the preparation of beta-amino alcohols with enantiomeric excesses up to 93%.

Facile Enantioselective Ring‐Opening Reaction of meso Epoxides with Anilines Using (S)‐(–)‐BINOL‐Ti Complex as a Catalyst

“…[15,21] The ring opening of meso-stilbene oxide with aniline using (S)-(BINOL)-Ti in the presence of different solvents suggests that toluene ( [15,21] We have also used the catalyst 1 for the ring opening of cyclohexene oxide (8) with different anilines 6a-c, where trans-amino alcohols were obtained in excellent yields with moderate enantioselectivity (Table 5). The catalyst 1 was found to be very active for the ring opening of cyclohexene oxide with aniline in the presence of triphenylphosphane (TPP) ( Table 5, Entry 23) giving 92 % isolated yield and 39 % ee in 2 h. These results are significantly superior as compared to the report where lanthanide iodobinaptholate [25] was used as a catalyst for a similar reaction which gave 55 % yield with 20 % ee in 18 h. The absolute configuration was determined by comparing the optical rotation and the HPLC profile with literature. Details are given in the Experimental Section.…”

“…These data can be obtained free of charge from The Cambridge Crystallographic Data Center via www.ccdc.cam.ac.uk/data_request/cif. [26,27] The title compound was isolated by column chromatography (hexane/AcOEt [26,27] The title compound was isolated by column chromatography ( (1R,2R)-2-(2-Methoxyphenylamino)-1,2-diphenylethanol (7c): [26] The title compound was isolated by column chromatography (hex- , OH), 3.79 (s, 3 H 64.9, 78.3, 109.6, 111.7, 117.1, 121.0, 126.7, 127.3, 127.7, 128.0, 128.3, 131.1, 140.2, 140.7, 140.6, 147.3 (1S,2S)-2-(Phenylamino)cyclohexen-1-ol (9a): [22,25,27] The title compound was isolated by column chromatography (hexane/AcOEt, …”

“…[21] However, until now, this area has been scarcely studied. [15] Nevertheless, various lanthanides [21,[22][23][24][25] with (R)/(S)-BINOL, Cr(Salen) [26] and Sc(bipyridine) [27] have been employed as catalysts for ringopening of meso epoxide with alkyl/arylamines to generate β-amino alcohols. Herein, we report the opening of mesostilbene oxide and cyclohexene oxide with aniline and substituted anilines, catalyzed by the recoverable (S)-BINOLTi complex to get enantio-enriched syn-β-amino alcohols and trans-β-amino alcohols in high yield (up to 95 %) with 78 % enantiomeric excess at ambient temperature.…”

Silica Chloride Nano Particle Catalyzed Ring Opening of Epoxides by Aromatic Amines

“…However, this methodology suffers from one or more disadvantages such as high toxicity and corrosiveness of the acids employed, moisture sensitivity of catalyst systems, high temperature, hazardous organic solvent, extended time and the use of catalyst in a stoichiometric amount or inconvenient handling procedures. [9][10][11] Therefore, continuous efforts have been made to develop catalyst-free metohd 12 and various catalysts such as sulfamic acid, 13 metal triflates, 14 metal alkoxides, 15 metal halides, 16 transition metal salts, 17 heteropolymolybdate or tungstate, 18 for the synthesis of β-amino alcohols. Other limitations such as low yields, failure of deactivated amines and sterically demanding aromatic amines are associated with most of the literature methods.…”

A New Strategy for the Aminolysis of Epoxides with Amines Under Solventfree Conditions Using Fe-Mcm-41 as a Novel and Efficient Catalyst

“…They are also used as blockers, insecticidal agents and as chiral ligands in asymmetric synthesis [2]. Several methods have been reported in the literature for the synthesis of b-aminoalcohols and several catalysts including sulfamic acid [6] Amberlyst-15 [7] metal triflates [8] metal alkoxides [9] metal halides [10,11] transition metal salts [12,13] heteropolymolybdate or tungstate [14] monodispersed silica nanoparticles [15] zeolites [16] montmorillonite clay [17], and ionic liquids [18] have been reported for this synthesis. However, the use of hazardous organic solvents, low catalytic efficiency and product selectivity, and non-reusability of the catalyst system are some of the issues with the existing methods.…”