221467-81-8Relevant articles and documents
Synthesis of enantiopure β- and γ-amino alcohols from homochiral α- and β-aminoacylsilanes as stable synthetic equivalents of α- and β-amino aldehydes
Bonini, Bianca Flavia,Comes-Franchini, Mauro,Fochi, Mariafrancesca,Gawronski, Jacek,Mazzanti, Germana,Ricci, Alfredo,Varchi, Greta
, p. 437 - 445 (2007/10/03)
A practical route is described for the synthesis of enantiopure β- and γ-amino alcohols with two stereocenters, starting from homochiral α- (1 and 5) and β- (13 and 16) -aminoacylsilanes, and involving stereoselective addition of allylmetal compounds and subsequent stereospecific protiodesilylation of the adducts. The degree of diastereoselectivity achieved in the nucleophilic addition step depends on both the nitrogen- protecting group and the reagents used. Diastereomeric excess (de) values equal to or higher than 98% were obtained in the TiCl4-promoted allylation of the N-Pht aminoacylsilanes 1 and 13 and of the N-Ts-aminoacylsilane 5 with allyltrimethylsilane. Lower de values were obtained in the Sc(OTf)3- catalyzed anylation of 5 with tetraallyltin and in the additions of both allyltrimethylsilane and tetraallyltin to the N-Ts-β-aminoacylsilane 16. Protiodesilylation of the adducts, leading to the β- and γ-amino alcohols, was accomplished with TBAF, except in the case of the adducts obtained from 5. For these, a preliminary removal of the tosyl group was necessary, which was accomplished with simultaneous desilylation by treatment with Na in liquid ammonia.
Newly designed acylsilanes as versatile tools in organic synthesis
Bonini, Bianca F.,Comes-Franchini, Mauro,Fochi, Mariafrancesca,Mazzanti, Germana,Ricci, Alfredo
, p. 181 - 189 (2007/10/03)
Structural variations in acylsilane molecules allow a number of new selective synthetic processes to be performed which lead to sulfur-containing heterocycles, highly functionalized and unsaturated polycarbonyl derivatives, polyenes, and β- and γ-aminoalcohols. The synthesis of these compounds, most of them not easily accessible through conventional routes, takes advantage of the site-selective reactions occurring at the C-Si bonds, of the increased stability of acylsilanes with respect to that of the corresponding aldehydes and of the high diastereofacial selectivity introduced by the SiR3 group. Herein we report the different synthetic strategies leading to the synthesis of several functionalized acylsilanes and their synthetic applications. The use of new selective polymetallic reagents for the nucleophilic silylation will be presented as well.
