Synthesis of Enantiopure β- and γ-Amino Alcohols from Homochiral α- and β-Aminoacylsilanes as Stable Synthetic Equivalents of α- and β-Amino Aldehydes

✍ Scribed by Bianca Flavia Bonini; Mauro Comes-Franchini; Mariafrancesca Fochi; Jacek Gawronski; Germana Mazzanti; Alfredo Ricci; Greta Varchi

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 206 KB
• Volume: 1999
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/(sici)1099-0690(199902)1999:2<437::aid-ejoc437>3.0.co;2-v

✦ Synopsis

aminoacylsilanes 1 and 13 and of the N-Ts-aminoacylsilane 5 with allyltrimethylsilane. Lower de values were obtained A practical route is described for the synthesis of enantiopure β-and γ-amino alcohols with two stereocenters, starting from in the Sc(OTf) 3 -catalyzed allylation of 5 with tetraallyltin and in the additions of both allyltrimethylsilane and tetraallyltin homochiral α-(1 and 5) and β-(13 and 16) -aminoacylsilanes, and involving stereoselective addition of allylmetal to the N-Ts-β-aminoacylsilane 16. Protiodesilylation of the adducts, leading to the β-and γ-amino alcohols, was compounds and subsequent stereospecific protiodesilylation of the adducts. The degree of diastereoselectivity achieved in accomplished with TBAF, except in the case of the adducts obtained from 5. For these, a preliminary removal of the tosyl the nucleophilic addition step depends on both the nitrogenprotecting group and the reagents used. Diastereomeric group was necessary, which was accomplished with simultaneous desilylation by treatment with Na in liquid excess (de) values equal to or higher than 98% were obtained in the TiCl 4 -promoted allylation of the N-Pht-ammonia.