Total Synthesis of (+)‐Elacomine and (−)‐Isoelacomine, Two Hitherto Unnamed Oxindole Alkaloids from Elaeagnus commutata

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.