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Total Synthesis of (+)‐Elacomine and (−)‐Isoelacomine, Two Hitherto Unnamed Oxindole Alkaloids from Elaeagnus commutata
Author(s) -
Pellegrini Claudio,
Weber Michael,
Borschberg HansJürg
Publication year - 1996
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19960790116
Subject(s) - chemistry , oxindole , yield (engineering) , alkaloid , stereochemistry , botany , organic chemistry , catalysis , materials science , metallurgy , biology
Racemic elacomine ((±)‐ 2 ), a hemiterpene spiro oxindole alkaloid from Elaeagnus commutata , was synthesized in five steps from 6‐methoxytryptamine ( 19 ) in 16% overall yield ( Scheme 3 ). The final oxidative rearrangement of the corresponding β‐carboline precursor (±)‐ 21 furnished isoelacomine ((±)‐ 22 ) as a by‐product (6% overall yield). A more elaborate route that started from L ‐tryptophan furnished (+)‐ 2 and (−)‐ 22 with optical purities of 76% ( Scheme 4 ) and established the absolute configuration of these compounds. A reinvestigation of the alkaloidal content of the roots of E. commutata showed that both elacomine and isoelacomine occur naturally in racemic form.