Total Syntheses of (−)-Spirooliganones A and B

The enantioselective syntheses of (−)-spirooliganones A and B have been accomplished in eight steps from commercially available starting materials. Noteworthy transformations include a three-component hetero-Diels–Alder cycloaddition to construct the tetracyclic core of spirooliganones, a Sharpless asymmetric dihydroxylation, and a tandem oxidative dearomatization/cyclization to build the oxa-spiro cyclohexadienone skeleton. The straightforward syntheses were performed without protecting groups

Total Synthesis of (±)-Przewalskin B

A concise total synthesis of przewalskin B was accomplished from readily available diene 7. Key features of the synthesis involved a Diels–Alder reaction to install the A ring, a Claisen–Johnson rearrangement to establish the spiro-quaternary center, and a ring-closing metathesis (RCM) of a sterically crowded system to construct the cyclic enone moiety

Biomimetic Syntheses of Callistrilones A–E via an Oxidative [3 + 2] Cycloaddition

Concise total syntheses of callistrilones A–E have been achieved from <b>7</b> and commercially available α-phellandrene (<b>8</b>). The synthetic strategy, which was primarily inspired by the biogenetic hypothesis, was enabled by an oxidative [3 + 2] cycloaddition followed by a Michael addition and an intramolecular nucleophilic addition to construct the target molecules. Moreover, viminalin I was also synthesized, and its absolute configuration was unambiguously confirmed

Biomimetic Total Synthesis of (−)-Isatisine A

The biomimetic total synthesis of (−)-isatisine A, a novel alkaloid with an unprecedented fused tetracyclic skeleton, was accomplished in 8 steps from indole and 4,6-<i>O</i>-isopropylidene-protected glucal. The synthesis features a convergent synthetic strategy which relies on nucleophilic addition and a biomimetic benzilic ester rearrangement as key reactions