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[摘要]：This review relates the results that we obtained in the field of the total synthesis of (-)-indolizidine 167B, based on the intramolecular cyclodehydration of a 4-pyrrolylbutanal to a 5,6-dihydroindolizine core, according to "oxo" or "non oxo" methodology. In the former pathway the butanal was (R)-4-(pyrrol-1-yl)heptanal and originated from (R)-3-(pyrrol-1-yl)but-1-ene via rhodium-catalyzed hydroformylation. In the latter one the proper (R)-4-carboxyethyl-4-(pyrrol-1-yl)butanal intermediate was obtained from diethyl-2-(pyrrol-1-yl)pentanedioate via chemo- and regioselective reduction of the sole distal ester group. In both cases a diastereoselective hydrogenation of the final 5-n-propyl-5,6-dihydroindolizine gave the target compound. |
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