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A Concise Synthesis of R ‐(–)‐Cicutoxin, a Natural 17‐Carbon Polyenyne
Author(s) -
Gung Benjamin W.,
Omollo Ann O.
Publication year - 2009
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/ejoc.200801172
Subject(s) - chemistry , sonogashira coupling , yield (engineering) , natural product , triple bond , total synthesis , stereochemistry , combinatorial chemistry , carbon fibers , double bond , organic chemistry , medicinal chemistry , palladium , catalysis , algorithm , materials science , metallurgy , composite number , computer science
A concise synthesis of the natural polyenyne R ‐(–)‐cicutoxin ( 1 ) is described. After several trials, the successful synthesis commenced with three key fragments, R ‐(–)‐1‐hexyn‐3‐ol ( 8 ), 1,4‐diiodo‐1,3‐butadiene ( 9 ), and THP‐protected 4,6‐heptadiyn‐1‐ol ( 6 ). Sonogashira coupling of compound 9 with acetylenes 6 and 8 gave the 17‐carbon frame, which upon regioselective reduction of a triple bond with Red‐Al and removal of the THP protecting group afforded the natural product in four linear steps. The triply convergent synthesis gave R ‐(–)‐cicutoxin in 18 % overall yield. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)