Scalable Synthesis of N-Acylaziridines from N-Tosylaziridines
摘要:
N-Acylaziridines are important starting materials for the synthesis of chiral amine derivatives. The traditional methods for producing these activated aziridines have significant drawbacks. The gram scale synthesis of N-acylaziridines by deprotection of N-tosylaztridines and reprotection with N-hydroxysuccinimide derivatives is described. Mono- and disubstituted aziridines perform well, with complete retention of stereochemical purity. The consistently moderate yields are linked to the N-tosylaziridine deprotection step, while acylation with N-hydroxysuccinimide derivatives is highly efficient.
Catalytic Enantioselective Ring-Opening Reaction of<i>meso</i>-Aziridines with α-Isothiocyanato Imides
作者:Yi-Ming Cao、Fu-Ting Zhang、Fang-Fang Shen、Rui Wang
DOI:10.1002/chem.201300297
日期:2013.7.15
Open up your chemistry! By using cinchonine‐based trimeric quaternary ammonium salts as catalysts, meso‐aziridines can be ring‐opened, in an enantioselective manner, through nucleophilic addition of the sulfur atom of α‐isothiocyanato imides (see scheme; PG=protecting group). This synthetic method provides an efficient way to access useful chiral β‐aminothiooxazole compounds.
An asymmetric ring-opening reaction of meso-aziridines with TMSN3 was developed using a catalyst prepared from Y(OiPr)3 and chiral ligand 2 in a 1:2 ratio. Excellent enantioselectivity was realized from a wide range of substrates with a practical catalyst loading. The products were efficiently converted to enantiomerically enriched 1,2-diamines, which are versatile chiral building blocks for pharmaceuticals and chiral ligands. This reaction was applied to a catalytic asymmetric synthesis of Tamiflu, a very important anti-influenza drug containing a chiral 1,2-diamino functionality.
Catalytic Asymmetric Ring-Opening of<i>meso-</i>Aziridines with Malonates under Heterodinuclear Rare Earth Metal Schiff Base Catalysis
Catalytic asymmetric ring-opening of meso-aziridines with malonates is described. The combined use of two rare earth metal sources with different properties promoted the desired ring-opening reaction. A 1:1:1 mixture of a heterobimetallic La(O-iPr)(3)/Yb(OTf)(3)/Schiff base la (0.25-10 mol %) efficiently promoted the reaction of five-, six-, and seven-membered ring cyclic meso-aziridines as well as acyclic meso-aziridines with dimethyl, diethyl, and dibenzyl malonates, giving chiral cyclic and acyclic gamma-amino esters in 99-63% yield and > 99.5-97% ee.
Highly Enantioselective Synthesis of β-Amidophenylthioethers by Organocatalytic Desymmetrization of <i>meso</i>-Aziridines
作者:Giorgio Della Sala、Alessandra Lattanzi
DOI:10.1021/ol901209n
日期:2009.8.6
The desymmetrization of N-acylaziridines with Me3SiSPh, catalyzed by commercially available (R) and (S)-VAPOL hydrogen phosphate, produced beta-(N-acylamino)phenylthioethers in a highly enantioselective and efficient manner (78-99% ee). The selection of the suitable aziridine/nucleophile/catalyst molar ratio is crucial to obtain high ee's.
Catalytic Enantioselective Desymmetrization of meso-Aziridines with Fluoromalonates
Catalytic enantioselective desymmetrization of meso-aziridines with fluoromalonates is described. Optimization studies revealed that the appropriate combination of Bronsted basic metal and Lewis acidic metal is important for promoting the reaction using fluoromalonates. A heterodinuclear Gd(OiPr)(3)/Y(OTf)(3)/Schiff base = 1:1:1 was the best catalyst, and ring-opening adducts, synthetic precursors for alpha-fluoro-gamma-amino acids, were obtained in 98%similar to 17% yield and >99.5%similar to 99% ee. Transformation of the ring-opening adduct into alpha-fluoro-gamma-lactam was also demonstrated.