This review surveys the total syntheses of sulfur-containing natural products where sulfur atoms are introduced with different sulfurization agents to construct related sulfur-containing moieties.

A palladium-catalyzed regiodivergent C1 insertion multicomponent reaction involving aryne, CO, and 2-iodoaniline is established to construct the scaffolds of phenanthridinone and acridone alkaloids. Regioselective control is achieved under the guidance of selective ligands. The phenanthridinones are solely obtained under ligand-free condition. In comparison, application of the electron-abundant bidentate ligand dppm afforded the acridones with high efficiency. The release rate of the aryne from the precursor assists the regioselectivity of insertion as well, which was revealed through interval NMR tracking. A plausible mechanism was suggested based on the control experiments. Representative natural products and two types of natural product analogues were synthesized divergently through this tunable method.

A uniformly strategic total synthesis of Aspidosperma alkaloids (+)-vincadifformine, (-)-quebrachamine, (+)-aspidospermidine, (-)-aspidospermine, (-)-pyrifolidine, and nine others from efficiently constructed tricyclic ketone 13 is reported. Highlights of these divergent and practical syntheses include (i) stereoselective intermolecular [4 + 2] cycloaddition to establish a C-E ring with one all-carbon quaternary stereocenter (C-5) and two bridged contiguous cis-stereocenters (C-12 and C-19), (ii) a Pd/C-catalyzed hydrogenation/deprotection/amidation cascade process to assemble the D ring, and (iii) Fischer indolization to forge the A-B ring.

A concise and stereocontrolled strategy for the syntheses of oxygenated Aspidosperma and Vinca alkaloids, via a stereoselective intermolecular inverse-electron-demand [4 + 2] cycloaddition, a challenging α,β-unsaturated ketone indolization rearrangement with excellent regio- and stereoselectivity, and an efficient Pd/C-catalyzed one-pot cascade reaction. The strategy has been demonstrated by the efficient asymmetric syntheses of antitumor drug (+)-vinblastine and five other oxygenated Aspidosperma alkaloids.

A comprehensive and updated summary of asymmetric organocatalytic annulation reactions is presented; in particular, the applications of these annulation strategies to natural products synthesis are highlighted.