The use of photochemical transformations is a powerful strategy that allows for the formation of a high degree of molecular complexity from relatively simple building blocks in a single step. A central feature of all light-promoted transformations is the involvement of electronically excited states, generated upon absorption of photons. This produces transient reactive intermediates and significantly alters the reactivity of a chemical compound. The input of energy provided by light thus offers a means to produce strained and unique target compounds that cannot be assembled using thermal protocols. This review aims at highlighting photochemical transformations as a tool for rapidly accessing structurally and stereochemically diverse scaffolds. Synthetic designs based on photochemical transformations have the potential to afford complex polycyclic carbon skeletons with impressive efficiency, which are of high value in total synthesis.

Photochemical Approaches to Complex Chemotypes: Applications in Natural Product Synthesis

Chemical analysis and quality control of Ginkgo biloba leaves, extracts, and phytopharmaceuticals

Chemical analysis of Ginkgo biloba leaves and extracts.

Strategies for the total synthesis of complex natural products that contain two or more contiguous stereogenic quaternary carbon atoms in their intricate structures are reviewed with 12 representative examples. Emphasis has been put on methods to create quaternary carbon stereocenters, including syntheses of the same natural product by different groups, thereby showcasing the diversity of thought and individual creativity. A compendium of selected natural products containing two or more contiguous stereogenic quaternary carbon atoms and key reactions in their total or partial syntheses is provided in the Supporting Information.

/pdf/synthetic-strategies-toward-natural-products-containing-20bttg89an.pdf

M. Alauddin

Papers

Structure of bilobalide, a rare tert-butyl containing sesquiterpenoid related to the C20-ginkgolides

Struktur von bilobalid, einem seltenen, tert.-butyl enthaltenden sesquiterpenoid, verwandt den c(20)ginkgoliden