Tailored Synthesis of Skeletally Diverse Stemona Alkaloids through Chemoselective Dyotropic Rearrangements of β-Lactones.
The collective synthesis of skeletally diverse Stemona alkaloids featuring tailored dyotropic rearrangements of β-lactones as key elements is described. Specifically, three typical 5/7/5 tricyclic skeletons associated with stemoamide, tuberostemospiroline and parvistemonine were first accessed through chemoselective dyotropic rearrangements of β-lactones involving alkyl, hydrogen, and aryl migration, respectively. By the rational manipulation of substrate structures and reaction conditions, these dyotropic rearrangements proceeded with excellent efficiency, good chemoselectivity and high stereospecificity. Furthermore, several polycyclic Stemona alkaloids, including saxorumamide, isosaxorumamide, stemonine and bisdehydroneostemoninine, were obtained from the aforementioned tricyclic skeletons through late-stage derivatizations. A novel visible-light photoredox-catalyzed formal [3+2] cycloaddition was also developed, which offers a valuable tool for accessing oxaspirobutenolide and related scaffolds.
['Guo|Zhen|Z|', 'Bao|Ruiyang|R|', 'Li|Yuanhe|Y|', 'Li|Yunshan|Y|', 'Zhang|Jingyang|J|', 'Tang|Yefeng|Y|0000-0002-6223-0608']
D000470:Alkaloids D061565:Cycloaddition Reaction D007783:Lactones D008027:Light D008968:Molecular Conformation D010084:Oxidation-Reduction D055668:Photochemical Processes D041901:Stemonaceae
alkaloids dyotropic rearrangement natural products photoredox catalysis total synthesis