http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Beta-lactones as synthetic vehicles in natural product synthesis
total syntheses of schulzeines B & C and omphadiol, and studies toward the total syntheses of scabrolides A & B and sinulochmodin C
β-Lactones are a class of structurally unique compounds. The versatile reactivity patterns offered by β-lactones have enable chemists to utilize them as powerful synthetic vehicles in complex molecule synthesis. In the total syntheses of the naturally occurring, α-glucosidase inhibitors schulzeines B & C, a readily available trichloromethyl β-lactone was used as a versatile masked surrogate for bishomoserine aldehyde, which led to a highly efficient construction of the core structures through a pivotal Pictet-Spengler condensation and a Corey-Link reaction. The first total synthesis of (+)-omphadiol was achieved in ten steps from (R)-carvone. This synthesis features a three-step synthesis of a bicyclic β-lactone, which constitutes the key intermediate for the highly stereocontrolled introduction of the six contiguous stereogenic centers in the natural product. In efforts toward the total syntheses of scabrolides A & B and sinulochmodin C via transannular C-H insertions, β-lactones served as the key intermediates for the synthesis of complex macrocyclic model substrates. These model studies provided valuable insights into the reactivity and selectivity issues for transannular C-H insertion reactions.
Doctor of Philosophy Texas A&M University 2011 http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10494