Synthesis of β-lactams by condensation of the tin enolates of 2-pyridylthioesters with imines. A comparison between titanium and tin enolates
作者:Rita Annunziata、Maurizio Benaglia、Mauro Cinquini、Franco Cozzi、Laura Raimondi
DOI:10.1016/s0040-4020(01)85649-0
日期:1994.1
SnBr4 affords the corresponding tin(IV) enolates that add to imines to give β-lactams in fair to good yields and with various degree of trans/cis stereoselectivity. Examples of highly diastereofacially selective reactions carried out on a chiral thioester and on a chiral imine are also reported. The results are compared with those obtained in the condensations promoted by TiCl4 and TiBr4.
将三乙胺加到2-吡啶基硫代酯和SnCl 4或SnBr 4的混合物中,得到相应的锡(IV)烯醇盐,它们加到亚胺上,以公平至良好的收率和不同程度的反式/顺式立体选择性得到β-内酰胺。还报道了在手性硫酯和手性亚胺上进行的高度非对映选择性反应的实例。将结果与由TiCl 4和TiBr 4促进的缩合中获得的结果进行比较。