Stereoselective Pd-catalyzed etherification and asymmetric synthesis of furanomycin and its analogues from a chiral aziridine

Abstract

A chiral aziridine was utilized for the synthesis of the anti-bacterial natural amino acid L-(+)-furanomycin, and its analogues including 5'-epi-furanomycin and norfuranomycin. Key steps of this synthesis are the stereoselective Pd-catalyzed etherification for diallyl ethers and ring closing metathesis.

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

“…ʟ-(+)-Furanomycin (Scheme 35) is a natural nonproteinogenic amino acid which showed pronounced antibacterial activity. From several syntheses of this compound the general approach which employs the aziridine ester (2 R ,1' R )- 5b as a starting material allows to also obtain its 5'-epimer and norfuranomycin (2 S ,2' R )- 133 [87]. To construct the 2,5-dihydrofurane ring the aziridine alcohol (2 R ,1' R ,1'' R )- 134 (Scheme 35) [88] was converted to the allyl ether (2 R ,1' R ,1'' R )- 135 which in the presence of Grubbs 1st generation catalyst produced (2 R ,1' R ,1'' R )- 136 .…”

NHC-Catalyzed Aldol-Like Reactions of Allenoates with Isatins: Regiospecific Syntheses of γ-Functionalized Allenoates

“…To continue our work on NHC-catalyzed reactions, we shall report herein an unknown example of NHC-promoted γ-specific diastereoselective aldol-like addition of allenic esters to isatins (Scheme c). This strategy also provided a shortcut to 2,3-allenol derivatives, which served as not only the platform intermediates for the syntheses of the natural products including (+)-Furanomycin, Liatrin, Capsochrom, and so on but also the precursors to construct cyclic skeletons such as lactones, lactams, and benzene …”

Brønsted Base-Mediated Aziridination of 2-Alkyl-Substituted-1,3-Dicarbonyl Compounds and 2-Acyl-Substituted-1,4-Dicarbonyl Compounds by Iminoiodanes

“…As a consequence, this has prompted a significant amount of effort toward the development of a myriad of synthetic methods to efficiently and selectively prepare the three-membered nitrogencontaining heterocycle. [24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] As part of an ongoing program exploring the reaction chemistry of iminoiodanes, we recently reported a facile synthetic approach to ,diacylaziridines involving Cu(II)-catalyzed aziridination of 2alkyl-substituted 1,3-dicarbonyl compounds with p-TsN=IPh (Scheme 1a). [38] Building on this initial work, we queried whether the construction of the aziridine motif in this manner could be achieved in the analogous reactions under transition metal-free mediated conditions (Scheme 1b).…”