| Phosphenes are a kind of in-situ generated highly active intermediates,the phosphorus ananlogues of ketenes.According to the Staudinger cycloaddition reactions,ketenes can undergo a[2+2]cycloaddition reaction with imine compounds to form β-lactam compounds.The β-lactam compounds are not only common intermediates in organic synthetic chemistry,but also an important pharmacophore of some antibiotics.As structural analogs of β-lactam compounds,organic chemists and pharmacologists have conducted extensive and in-depth studies on the synthesis of β-lactam and β-sultam compounds,but for less attention has been paid to β-phosphonolactams and fi-phosphinolactams.With the goal of synthesizing fi-phosphinolactams,a class of phosphene intermediates were synthesized in this dissertation,and the target products were synthesized by their reactions with imines.In this dissertation,a-diazoarylmethyl(diaryl)phosphine oxides are selected as the phosphene precursors,which are initiated by microwave heating and react with imines to carry out the synthesis of βphosphinolactams.Firstly,a-diazobenzyl(diphenyl)phosphine oxide was synthesized as the phosphene precursor,and it was found that it reacted with α,β-unsaturated imines under microwave heating conditions,and βphosphinolactam was successfully synthesized.Then the reaction conditions were further optimized.Under the optimal reaction conditions,it reacted with different unsaturated imine substrates to expand the applicability of the reaction,and it was also tried to the reaction with aryl substituted imines,achieving good results as well.The reaction mechanism is that the Wolff rearrangement of α-diazoarylmethyl(diaryl)phosphine oxide compounds generates phosphene intermediates under microwave heating conditions.The nucleophilic addition of imines to the phosphenes and subsequent intramolecular cyclization afford β-phosphinolactams.In addition,the microwave-assisted reactions of αdiazoarylmethyl(diaryl)phosphine oxide compounds with other types of imines and unsaturated aldehyde and ketone substrates have also been studied.We have found that for different reaction substrates generated different products.In general,the research on the reactions of phosphenes produced fromα-diazoarylmethyl(diaryl)phosphine oxides with unsaturated imines has achieved good results,creating a new method for the preparation of βphosphinolactams from phosphenes.At the same time,the reactions of other types of unsaturated substrates with phosphenes were seriously affected by the structure of the substrates. |
