Study On Asymmetric Ring Expansion Of Diazophosphates With 4-substituted Cyclohexanones

In this thesis,two methods were studied for asymmetric ring expansion reaction of 4-substituted cyclohexanones with diazophosphonates:the first was that racemicβ-hydroxydiazophosphonate compounds were obtained with up to moderate yields by the Aldol reaction of ketones and diazophosphonates in the catalysis of basesand tried to achieve the enantioselective de-symmetry through pinacol rearrangement reaction and give seven-membered ring ketone in the catalysis of a series of chiral Lewis acids or BrΦnsted acids.However,the result was disapointed;the second method was that the desymmetry of 4-substituted cyclohexanones were realized by tandem Aldol-ring expansion reaction in the catalysis of chiral Lewis acid.The optimal reaction conditions were established after screening of Lewis acids and chiral ligands,and optimizing reaction conditions.,Seven-membered cycloketones with two chiral centers could be achieved in good yields,and up to 91%ee when the reaction proceeded under the optimal conditions as:in the catalysis of chiral complex derived from 3,3′-iodo-substituted chiral binaphthol as ligand and BF₃·Et₂O as Lewis acid;in the presence of4?MS for 5 days at-20 ^oC..This thesis has established a new method for access optically active 2-phosphonyl cycloheptanone derivatives.