794528-61-3Relevant academic research and scientific papers
Synthesis of the Proposed Structures of Parvistemoamide and Their Transformations to Stemoamide Derivatives
Cao, Fei,Gao, Weiwei,Wang, Xiaodong,Zhang, Zhihan,Yin, Gaofeng,Wang, Yuqing,Li, Zhao,Shi, Tao,Hou, Yongsheng,Chen, Jinhong,Wang, Zhen
, p. 6222 - 6226 (2021)
The proposed structures of parvistemoamide have been achieved by macrolactamization, but none of the characterization data of synthetic samples matched with those of the natural sample. The transformation of the highly strained 10-membered lactam ring in parvistemoamide into the pyrrolo[1,2-a]-azepine nucleus in stemoamide is accomplished for the first time by either transannular cyclization or Pilli's transformation. This research may promote the total synthesis of other more complex stemoamide-type or medium-sized-ring-containing Stemona alkaloids.
Total Synthesis of Stemoamide, 9a- epi -Stemoamide, and 9a,10- epi -Stemoamide: Divergent Stereochemistry of the Final Methylation Steps
Siitonen, Juha H.,Csókás, Dániel,Pápai, Imre,Pihko, Petri M.
, p. 1581 - 1586 (2020)
Total syntheses of stemoamide, 9a- epi -stemoamide, and 9a,10- epi -stemoamide by a convergent A + B ring-forming strategy is reported. The synthesis required a diastereoselective late-stage methylation of the ABC stemoamide core that successfully enabled access to three of the four possible diastereomeric structures. For the natural stemoamide series, the diastereoselectivity can be rationalized both by kinetic and thermodynamic arguments, whereas for the natural 9a- epi -stemoamide series, the kinetic selectivity is explained by the prepyramidalization of the relevant enolate.
Total synthesis of (-)-stemoamide using ruthenium-catalyzed enyne metathesis reaction
Kinoshita, Atsushi,Mori, Miwako
, p. 287 - 299 (1997)
A total synthesis of (-)-stemoamide was achieved from (-)-pyroglutamic acid using a ruthenium-catalyzed enyne metathesis as a key step, in 14 steps in 9percent overall yield.
Pyrrole Strategy for the γ-Lactam-Containing Stemona Alkaloids: (±)Stemoamide, (±)Tuberostemoamide, and (±)Sessilifoliamide A
Yin, Xianglin,Ma, Kaiqing,Dong, Ying,Dai, Mingji
, p. 5001 - 5004 (2020)
Stemona alkaloids contain family members with diverse structural scaffolds. Many of them feature a γ-lactam ring embedded in their characteristic 5-7-5 fused tricyclic core. Herein a pyrrole strategy was developed to enable the total syntheses of three Stemona alkaloids: (±)stemoamide, (±)tuberostemoamide, and (±)sessilifoliamide A. In these cases, a substituted pyrrole was used as the γ-lactam precursor. A sequential pyrrole oxidation and enamide reduction were realized to convert the pyrrole to the corresponding γ-lactam in those three natural products. The use of a pyrrole in an early stage of the synthesis offers the advantage of rapid construction of the key intermediates by exploiting its nucleophilicity.
Bioinspired and concise synthesis of (±)-stemoamide
Wang, Yan,Zhu, Lili,Zhang, Yuying,Hong, Ran
, p. 2787 - 2790 (2011)
Natural inspiration: A concise total synthesis of (±)-stemoamide was completed in eight steps with a 37 % overall yield. A bioinspired N-acyliminium ion cyclization and an unprecedented dynamic ruthenium-catalyzed cyclocarbonylation ensured the high efficiency of the synthesis. A novel silver-mediated cyclization of an allenic alcohol shows potential for the future asymmetric synthesis of the target. TMS=trimethylsilyl. Copyright
Lactam Strategy Using Amide-Selective Nucleophilic Addition for Quick Access to Complex Amines: Unified Total Synthesis of Stemoamide-Type Alkaloids
Chida, Noritaka,Ogihara, Chisato,Oishi, Takeshi,Sato, Takaaki,Shibuya, Kana,Soda, Yasuki,Sugiyama, Yasukazu,Tajima, Hayato,Takahashi, Yoshito,Yokoyama, Takashi,Yoritate, Makoto
supporting information, p. 278 - 287 (2022/03/17)
Our research group has been exploring a lactam strategy for the concise total synthesis of complex alkaloids. In this article, we report full details of the unified total synthesis of stemoamide-type alkaloids by chemoselective assembly of five-membered rings based on the lactam strategy. First, the concise and gram-scale synthesis of tricyclic stemoamide was achieved by vinylogous Michael addition-reduction sequence of an unsaturated γ-lactam with an unsaturated γ-lactone, followed by N-alkylation to form the seven-membered ring. From stemoamide as a common intermediate, chemoselective nucleophilic addition of unsaturated lactone derivatives provides tetracyclic natural products. While stemonine is obtained by an Ir-catalyzed lactam-selective reductive Mannich reaction, saxorumamide and isosaxorumamide are produced through the lactone-selective nucleophilic addition of the lithiated 2- silyl furan. The developed conditions for the lactam-selective nucleophilic reactions are highly general, and were found to be applicable to the total synthesis of pentacyclic stemocochinin and isostemocochinin. The strategy enables the concise and unified total synthesis of tricyclic, tetracyclic and pentacyclic stemoamide-type alkaloids within 12 steps from a commercially available compound.
Tailored Synthesis of Skeletally Diverse Stemona Alkaloids through Chemoselective Dyotropic Rearrangements of β-Lactones
Guo, Zhen,Bao, Ruiyang,Li, Yuanhe,Li, Yunshan,Zhang, Jingyang,Tang, Yefeng
, p. 14545 - 14553 (2021/05/31)
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.
Unified Total Synthesis of Stemoamide-Type Alkaloids by Chemoselective Assembly of Five-Membered Building Blocks
Yoritate, Makoto,Takahashi, Yoshito,Tajima, Hayato,Ogihara, Chisato,Yokoyama, Takashi,Soda, Yasuki,Oishi, Takeshi,Sato, Takaaki,Chida, Noritaka
, p. 18386 - 18391 (2017/12/15)
A unified total synthesis of stemoamide-type alkaloids is reported. Our synthetic approach features the chemoselective convergent assembly of five-membered building blocks via stemoamide as the common precursor to tetracyclic natural products. The synthesis consists of two successive coupling reactions of the three five-membered building blocks. The first coupling reaction is the vinylogous Michael addition/reduction sequence, which enables the gram-scale synthesis of stemoamide. The second coupling reaction is a chemoselective nucleophilic addition to stemoamide. While the lactone-selective nucleophilic addition to stemoamide affords saxorumamide and isosaxorumamide, the lactam-selective reductive nucleophilic addition leads to the formation of stemonine. Both chemoselective nucleophilic additions enable direct modification of stemoamide, resulting in highly concise and efficient total syntheses of the stemoamide-type alkaloids.
Total Synthesis of (-)-Stemoamide by Sequential Overman/Claisen Rearrangement
Nakayama, Yasuaki,Maeda, Yuichiro,Hama, Naoto,Sato, Takaaki,Chida, Noritaka
, p. 1647 - 1654 (2016/05/24)
The enantioselective total synthesis of (-)-stemoamide using Overman/Claisen rearrangement of an allylic 1,2-diol is reported. The enantiopure allylic 1,2-diol was efficiently prepared from naturally occurring dimethyl tartrate. The chirality transfer reactions through two consecutive [3,3]-sigmatropic rearrangements proceeded with complete diastereoselectivity in a one-pot process.
Umpolung of hemiaminals: Titanocene-catalyzed dehydroxylative radical coupling reactions with activated alkenes
Zheng, Xiao,Dai, Xi-Jie,Yuan, Hong-Qiu,Ye, Chen-Xi,Ma, Jie,Huang, Pei-Qiang
, p. 3494 - 3498 (2013/04/24)
Radical measures: A radical coupling reaction, which is proposed to proceed through in situ chlorination of a hydroxy group by Me3SiCl, is used to form quaternary carbon centers with amino groups in α position. The reaction can be scaled up and
