19351-63-4Relevant articles and documents
Total Synthesis of (-)-Strictosidine and Interception of Aryne Natural Product Derivatives "strictosidyne" and "strictosamidyne"
Anthony, Sarah M.,Tona, Veronica,Zou, Yike,Morrill, Lucas A.,Billingsley, John M.,Lim, Megan,Tang, Yi,Houk,Garg, Neil K.
, p. 7471 - 7479 (2021)
Monoterpene indole alkaloids are a large class of natural products derived from a single biosynthetic precursor, strictosidine. We describe a synthetic approach to strictosidine that relies on a key facially selective Diels-Alder reaction between a glucosyl-modified alkene and an enal to set the C15-C20-C21 stereotriad. DFT calculations were used to examine the origin of stereoselectivity in this key step, wherein two of 16 possible isomers are predominantly formed. These calculations suggest the presence of a glucosyl unit, also inherent in the strictosidine structure, guides diastereoselectivity, with the reactive conformation of the vinyl glycoside dienophile being controlled by an exo-anomeric effect. (-)-Strictosidine was subsequently accessed using late-stage synthetic manipulations and an enzymatic Pictet-Spengler reaction. Several new natural product analogs were also accessed, including precursors to two unusual aryne natural product derivatives termed "strictosidyne"and "strictosamidyne". These studies provide a strategy for accessing glycosylic natural products and a new platform to access monoterpene indole alkaloids and their derivatives.
Synthese von Secologanin
Tietze, Lutz-F.,Henke, Stephan
, p. 1005 (2007/10/02)
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SELECTIVE TRANSFORMATIONS OF SECOLOGANIN: DIHYDROXYLATION
Purdy, John Richard,Hamilton, Raymond G.,Akhter, Lalarukh,McLean, Stewart
, p. 210 - 214 (2007/10/02)
Sweroside tetraacetate ( 2b ) has been converted in high yield by osmylation to the epimeric glycols 3 and 4 ( R=H ) which have been separated.This reaction proceeds with high chemoselectivity for reaction at the vinyl side chain but with low stereoselectivity, leading to a small excess of the 3-R isomer.Secologanin derivatives appear to show a much lower chemoselectivity in this reaction, but the stereoselectivity is considerably higher, and opposite to that in the sweroside example.Conditions have been found for oxidizing the dimethylacetal 5b of secologanin tetraacetate in useful yields to the epimeric glycols 6 and 7 ( R=H ); in this reaction a large excess of the 3-S isomer is formed.The reasons for these differences in selectivity appear to be related to differences between the two series in conformational preference.