Advances in Lewis Acid Controlled Carbon−Carbon Bond-Forming Reactions Enable a Concise and Convergent Total Synthesis of Bullatacin
摘要:
Lewis acids control regioselectivity in the alkylation of epi-chlorohydrin and the stereochemistry of an alkyne addition to set the C24/C23 anti relationship. These advances facilitate an efficient total synthesis of bullatacin in 13.3% overall yield from commercial starting materials.
intermediates. N-Iodosuccinimide (NIS) effectively worked as an activator of the double bonds in the substrates and the silyl enol ether. Application to an expedient synthesis of the adjacent bis-tetrahydrofuran core of Annonaceousacetogenins with a cis/threo/cis relative stereochemistry is also described.
The most efficient method for the synthesis of the trans/threo/trans-bis(tetrahydrofuran) (THF) ring unit was established, and the first total synthesis of (−)-asimilobin and its diastereomer was then accomplished in twelve and fourteen steps, respectively, from trans-1,5,9-decatriene, by a convergentroute with a Wittig reaction as the key step. By virtue of these synthetic results, the absolute configuration
Rao, A. V. Rama; Reddy, K. L. N.; Reddy, K. Ashok, Indian Journal of Chemistry - Section B Organic and Medicinal Chemistry, 1993, vol. 32, # 12, p. 1203 - 1208
作者:Rao, A. V. Rama、Reddy, K. L. N.、Reddy, K. Ashok
DOI:——
日期:——
Selective Formation of trans/threo/cis and cis/threo/cis Bis-Tetrahydrofurans from the Same Diene Diols
Double intramolecular iodoetherification reactions of cyclic acetals and ketals, prepared from the same C-2-symmetric diene diol with aldehydes or ketones, stereoselectively afford trans/threo/cis or cis/threo/cis bis-TIE ring systems.
Alteration of the Bis-tetrahydrofuran Core Stereochemistries in Asimicin Can Affect the Cytotoxicity
作者:Subhash C. Sinha、Zhiyong Chen、Zheng-Zheng Huang、Eiko Nakamaru-Ogiso、Halina Pietraszkiewicz、Matthew Edelstein、Frederick Valeriote
DOI:10.1021/jm801028c
日期:2008.11.27
A systematic analysis using 10 synthetic asimicin stereoisomers revealed that the stereochemistry of the bis-tetrahydrofuran core, including the tetrahydrofuran rings and the adjacent hydroxy functions, had significant effect on its cytotoxicity. Our findings set to rest the highly controversial perception that the stereochemistry of the tetrahydrofuran core has little effect on the activity, which is not true for its cytotoxic effect, and also reinforces the previous conclusion that asimicin is a highly potent anticancer compound.