Total Synthesis of (+)-Antofine and (-)-Cryptopleurine
作者:Weijiang Ying、James W. Herndon
DOI:10.1002/ejoc.201300200
日期:2013.5
The tylophorine alkaloid anticancer compounds antofine and cryptopleurine have been synthesized in optically active form. Both syntheses employ optically pure α-amino acids as the starting materials, require only seven steps from known 2-ethynylpyrrolidine or 2-ethynylpiperidine derivatives, and are free of protecting groups. Key steps include an alkyne hydration and a chromium carbene complex based
Efficient and Chirally Specific Synthesis of Phenanthro-Indolizidine Alkaloids by Parham-Type Cycloacylation
作者:Ziwen Wang、Zheng Li、Kailiang Wang、Qingmin Wang
DOI:10.1002/ejoc.200900920
日期:2010.1
A concise, efficient and modular route involving Parham-type cycloacylation as the key step has been used to synthesize six enantiopure phenanthro-indolizidine alkaloids 1a-c. The preparation of enantiomericallypure tylophora alkaloids and their seco analogues on a large-scale is now feasible. The alcohol intermediates 8a-c, which are difficult to prepare by other synthetic methodologies, have been
A Simple Enantioselective Route to Functionalized Indolizidines: Synthesis of (+)-Ipalbidine and (+)-Antofine
作者:Sunil V. Pansare、Rajinikanth Lingampally、Rajendar Dyapa
DOI:10.1002/ejoc.201100125
日期:2011.4
efficient route to functionalizedindolizidines from an enantiomerically enriched γ-nitro ketone is described. The nitro ketone is obtained by an organocatalytic, enantioselective ketone-nitro alkene Michael addition. Oxidative ring expansion of the nitro ketone and subsequent methanolysis provides a 8-nitro-4-oxooctanoate. This is stereoselectively transformed to the key, functionalizedindolizidine intermediate
Total Syntheses of Arylindolizidine Alkaloids (+)-Ipalbidine and (+)-Antofine
作者:Micah J. Niphakis、Gunda I. Georg
DOI:10.1021/jo101051w
日期:2010.9.3
This paper presents the first application of two recently developed reactions to natural product synthesis. The first method involves a 6-endo-trig cyclization to prepare a versatile chiral enaminone building block. The second is a direct C-H arylation reaction. As a showcase for the utility of these methods, (+)-antofine and (+)-ipalbidine were synthesized in only 8 steps and 24-26% overall yields.
Total synthesis of phenanthroindolizidine alkaloids via asymmetric deprotonation of N-Boc-pyrrolidine
作者:Meng Deng、Bo Su、Hui Zhang、Yuxiu Liu、Qingmin Wang
DOI:10.1039/c3ra47465h
日期:——
A concise and efficient enantioselective strategy to synthesize two typical phenanthroindolizidine alkaloids, 14-hydroxyantofine and antofine, was developed, featuring an asymmetricdeprotonation/diastereoselective carbonyl addition sequence during which the formation of a chiral C-13a center and connection of pyrrolidine and phenanthrene moieties were achieved efficiently in one step. The absolute