Synthesis of tryptophans by Lewis acid promoted ring-opening of aziridine-2-carboxylates: optimization of protecting group and Lewis acid
                                
                                    
                                        作者:Ilaria Tirotta、Nathan L. Fifer、Julia Eakins、Craig A. Hutton                                    
                                    
                                        DOI:10.1016/j.tetlet.2012.11.139
                                    
                                    
                                        日期:2013.2
                                    
                                    The preparation of tryptophan derivatives through the Lewis acid promoted substitution of aziridine carboxylates with indole was found to be accompanied by a ring-expansion reaction to generate an oxazolidinone byproduct. The ratio of tryptophan to oxazolidinone products can be optimized through a judicious choice of Lewis acid and N-protecting group. (c) 2012 Elsevier Ltd. All rights reserved.