01409nas a2200169   4500008004100000022001400041245013700055210006900192260000800261300001600269490000600285520074200291100002801033700001901061700002801080856013101108       2019                        eng d  a2470-134300aUnusual epimerization in styryllactones: synthesis of (-)-5-hydroxygoniothalamin, (-)-5-acetylgoniothalamin, and O-TBS-goniopypyrone0 aUnusual epimerization in styryllactones synthesis of 5hydroxygon  cDEC  a22549-225560 v43 a<p>(-)-5-Hydroxygoniothalamin, (-)-5-acetylgoniothalamin, and (+)-5-hydroxygoniothalamin, isolated from the Goniothalamus genus, are synthesized from triacetyl-O-D-glucal by employing the Ferrier reaction, Mitsunobu reaction, and Jones oxidation as key steps. The synthetic procedure also yields the epimers of (-)-5-hydroxygoniothalamin and (+)-5-hydroxygoniothalamin employing acid-mediated transition-metal-free epimerization at C-5 of styryllactones. Further studies reveal that the epimerization is facilitated by the phenyl group present on the styryllactones. Also, depending on the dihydroxylation reaction conditions, various analogues of saturated styryllactones are synthesized utilizing oxa-Michael reaction conditions.</p>
1 aKotammagari, Tharun, K.1 aPaul, Sayantan1 aBhattacharya, Asish, K.  uhttps://library.ncl.res.in/content/unusual-epimerization-styryllactones-synthesis-5-hydroxygoniothalamin-5-acetylgoniothalamin