The first total syntheses of two cernuane-type Lycopodiumalkaloids, (-)-cernuine and (+)-cermizine D, were accomplished starting from (+)-citronellal. The syntheses involved organocatalytic alpha-amination to afford oxazolidinone, which is used for diastereoselective allylation, and asymmetric transfer aminoallylation followed by stereoselective construction of an aminal moiety as key steps.
syntheses of cernuane-type and quinolizidine-type Lycopodium alkaloids are described. A commonintermediate5 for the two types of alkaloids was assembled practically from (+)-citronellal via organocatalytic α-amination, followed by the construction of oxazolidinone that was used for diastereoselective allylation. Key compound 5 was converted into cermizine C (3), and this in turn was converted into senepodine
new phlegmarane-type alkaloids, cermizines A (1) and B (2), three new quinolizidine alkaloids, cermizine C (3) and senepodines G (4) and H (5), and a new C16N2 type alkaloid consisting of a quinolizidine and a piperidine ring, cermizine D (6), as well as two new cernuane-type alkaloids, cernuine N-oxide (7) and lycocernuine N-oxide (8), have been isolated together with cernuine (9) and lycocernuine
两种新的依帕玛烷型生物碱,cermizines A(1)和B(2),三种新的喹诺酮类生物碱,cermizine C(3)和senepodines G(4)和H(5),以及一种新的C 16 N 2型生物碱,由已分离出喹喔嗪和哌啶环中的cermizine D(6),以及两个新的cernuane型生物碱,cernuine N -oxide (7)和lycocernuine N- oxide (8),以及cernuine(9)和lycocernuine(10从球杆苔)石松cernuum和羊草(L. chinense)。的相对立体化学1 - 4和6,和的绝对立体化学5,7,和8通过NOESY的相关性,改性Mosher氏法,化学转化,和计算方法的组合阐明。cerrmizine D(6)可能是天竺葵型生物碱(例如7 – 10)的生物合成中间体。