Michael Addition Reaction Of Chiral Nickel (Ⅱ) - Diamine To Nitro Dienylene And Its Application In (+) - α-Lycorane Synthesis

Michael addition reaction is an important carbon-carbon bond-forming, the addition product can be used to transforme a lot of different useful organic compound. The1,4-asymmetric addition of conjugated nitrodienynes and the carbonyl compound was mainly targeted in studying. Based on this methodology, the total synthesis of (+)-a-lycorane and formal total synthesis of (+)-lycorine were complished.A novel conjugated nitrodienynes has been designed and synthesized for the asymmetric synthesis as a useful new class of Michael acceptors. The acceptors and the carbonyl compound were atised asymmetric1,4-addition reaction in the chiral nickel(II)-diamine, the product yield (85-95%), ee value of90%the above. The addition producs of di-tert-butyl malonate to nitro dienynes with a catalytic amount of TsOH afford enone acids by tandem reaction, and then enone acids were esterified to provide the enone esters.The enone ester underwent intramolecular Michael addition reaction to give key intermediate cyclohexanes. The asymmetric1,4-addition producs of nitro dienynes to tert-butyl acetoacetate with a catalytic amount of TsOH were afforded functionalized enantioenriched cyclic dienone by cascade reaction. In summary, a conjugated nitro dienynes have been developed with enantioselective and a good yield for asymmetry reactions. Moreover, we have developed a simple, yet flexible catalytic cascade approach to synthetically useful functionalized enantioenriched acyclic α,β-enones and cyclic dienones.The total synthesis of (+)-a-lycorane and formal total synthesis of (+)-lycorine were accomplished through a highly compact route from a functionalized chiral cyclohexanone intermediate.Total synthesis of (+)-a-lycorane was completed based on the key intermediate functionalized cyclohexanone, after1,2-ethanethiol protection, reduction, cyclization, reduction, etc. conversion, finally of an overall yield of1.9%. Formal synthesis of (+)-lycorinein was completed from the key intermediate in the synthesis of (+)-a-lycorane, via deprotection, reduction, protection, selective elimination of a series of realized, finally of an overall yield of1.1%.