The total synthesis of securinine and other methodology studies

Chapter 1 presents a flexible synthesis of (-)-securinine in 18 steps and 16% overall isolated yield from the commercially available trans-4-hydroxy-L-proline. Securinine is the major Securinega alkaloid isolated from the Securinega, which has been associated with a number of interesting biological activities. The key steps of the synthesis include the highly diastereoselective preparation of the spirocyclic α,β-unsaturated γ-lactone intermediate and the intramolecular Heck cyclization to complete the tetracyclic skeleton. We anticipate that the synthetic route can be readily modified to access other Securinega alkaloids (e.g. norsecurinine). In chapter 2 Acyclic Diaminocarbene (ADC) were studied as lignads in various C-C bond formation reactions (e.g. Suzuki-Miyaura, Sonogashira and Heck). ADCs are more basic than their counterpart NHCs and can be easily synthesized from the formamidinium salt precursors. The resulting coupling products obtained in good to excellent yields. Homoallylic amines are very useful synthons for numerous biologically active compounds. Chapter 3 presents facile syntheses of homoallylic amines using an easily executable three component system of ketone, ammonia, and allylboronates. The resulting homoallylic amines were isolated in good to excellent yields through simple acid-base extraction. The crotylation of N-unsubstituted ketimines was also shown to be highly diastereoselective