| Affiliation: | 1. Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN, 47405 USA These authors contributed equally to this work.;2. Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, IN, 47405 USA |
| Abstract: | We describe enantioselective syntheses of strychnos and chelidonium alkaloids. In the first case, indole acetic acid esters were established as excellent partner nucleophiles for enantioselective cooperative isothiourea/Pd catalyzed α-alkylation. This provides products containing indole-bearing stereocenters in high yield and with excellent levels of enantioinduction in a manner that is notably independent of the N-substituent. This led to concise syntheses of (−)-akuammicine and (−)-strychnine. In the second case, the poor performance of ortho-substituted cinnamyl electrophiles in the enantioselective cooperative isothiourea/Ir catalyzed α-alkylation was overcome by appropriate substituent choice, leading to enantioselective syntheses of (+)-chelidonine, (+)-norchelidonine, and (+)-chelamine. |
