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Epoxidation Studies on Lathyra‐6(17),12‐dienes − Revised Structure of the Euphorbia Factor L 1
Author(s) -
Appendino Giovanni,
Cravotto Giancarlo,
Jarevång Tomas,
Sterner Olov
Publication year - 2000
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200008)2000:16<2933::aid-ejoc2933>3.0.co;2-j
Subject(s) - chemistry , dioxirane , trifluoromethyl , natural product , yield (engineering) , double bond , epoxide , stereochemistry , organic chemistry , enantioselective synthesis , alkyl , catalysis , materials science , metallurgy
As part of an investigation aimed at mimicking certain steps of the biogenesis of the polycyclic Euphorbia diterpenoids from macrocyclic precursors, the epoxidation of lathyrol and its esters with (peroxy/peroxo)metal complexes and non‐metal (peracids and dioxiranes) oxidants was investigated. Treatment of lathyrol esters with methyl(trifluoromethyl)dioxirane gave 6(17)β‐epoxides as the only reaction products in very high yield. Conversely, lathyrol itself proved amenable to epoxidation only with the TBHP−VO(acac) 2 protocol. Surprisingly, the reaction was not chemoselective, and also the enone double bond was epoxidized, eventually affording a rearranged compound of the 14(13→12)‐ abeo‐ lathyrane type. Based on the stereochemical course of the epoxidation of lathyrol esters and on NMR experiments on the natural product, the configuration at C‐6 of the Euphorbia Factor L 1 was revised, overturning a thirty‐year misconception on the structure of this compound.