An efficient total synthesis of the revised structure of the sensitive triyne natural product, (4S,5S)-4,8dihydroxy-3,4-dihydrovernoniyne, and all of its stereoisomers, that is, the previously proposed (4S,5R), (4R,5R), and (4R,5S), has been accomplished from chiral pool compounds L-mannonic-γ-lactone and D-glucono-δ-lactone. The key features involve a one-pot conversion of the chiral pool compounds into the γ-vinyl-β-hydroxy-γ-lactones, the heteroatom-directed Wacker oxidation, the Seyferth−Gilbert reaction, and Cadiot−Chodkiewicz coupling. The synthesis also involves minimal protecting groups (only tertbutyldimethylsilyl) and is completed in seven to eight steps.

An efficient diastereoselective allylation of aldehydes with functionalized allyl bromolactone paved an excellent path toward the protecting-group-free divergent total synthesis of various guaianolides (+)-ligustrin, (+)-8-epi-ligustrin, and (+)-grosheimin and the formal synthesis of (−)-eupalinilide E. The key steps include diastereoselective allylation, efficient translactonization, and aldehyde–ene reaction. From the common intermediate molecule (+)-ligustrin, the first asymmetric total synthesis of (+)-grosheimin has been achieved.

An efficient chiral catalyst for the asymmetric epoxidation of α,β-unsaturated carbonyl compounds is developed utilizing easily available, eco-friendly CaCl 2 and chiral ligand. Efficacy of the methodology is extended for the stereoselective synthesis of (S)-Fenoprofen. A survey of ligands indicated that (S)-,6,6'-Diphenyl BINOL-Ca 1e was the best ligand giving maximum ee (84%) for 4 with excellent yield.

A catalytic asymmetric second generation synthesis of (4S,5S)-4,8-dihydroxy-3,4-dihydrovernoniyne has been completed employing the asymmetric dihydroxylation strategy. Further, a four-step protecting-group-free synthesis of the natural product and its enantiomer has been achieved through the modified Knoevenagel reaction, asymmetric dihydroxylation, and Cadiot–Chodkiewicz coupling. The protecting-group-free synthesis is completed in four steps and 41% overall yield.

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