Novel generation of azomethine imines from α-silylnitrosamines by 1,4-silatropic shift and their cycloaddition
                                
                                    
                                        作者:Ken-Ichi Washizuka、Keiko Nagai、Satoshi Minakata、Ilhyong Ryu、Mitsuo Komatsu                                    
                                    
                                        DOI:10.1016/s0040-4039(99)01859-6
                                    
                                    
                                        日期:1999.12
                                    
                                    Novel and facile generation of azomethine imines from alpha-silylnitrosamines and subsequent cycloaddition with dipolarophiles leading to a variety of pyrazole derivatives have been developed. The key to the reaction is a 1,4-silatropic shift caused by strong affinity of the nitroso oxygen atom toward the silicon atom. Thus, alpha-silylnitrosamines are treated with 1 equiv. of dipolarophiles in refluxing toluene for 1 h to give pyrazole derivatives in good to excellent yields. (C) 1999 Elsevier Science Ltd. All rights reserved.