Synthesis of β-lactams and β-aminoesters via high intensity ultrasound-promoted Reformatsky reactions
作者:Nathan A. Ross、Robert R. MacGregor、Richard A. Bartsch
DOI:10.1016/j.tet.2004.01.002
日期:2004.2
Reformatskyreactions of an imine, an α-bromoester, zinc dust and a catalytic amount of iodine in dioxane under high intensity ultrasound (HIU) irradiation from an ultrasonic probe are explored. A series of 16 aldimines with varying electronic demands is evaluated as potential electrophiles for reactions with three α-bromoesters of differing steric demands. This HIU method is successful for both enolizable
An efficient method for one-pot synthesis of β-lactams from aldimines and ketene silyl acetals by tandem Lewis base-catalyzed Mannich-type addition and cyclization, namely reaction of benzylideneanilines and trimethylsilyl enolates derived from esters or thioesters was established by using a Lewis base catalyst such as lithium acetate, N-lithio-2-pyrrolidone, potassium salt of phthalimide or lithium