טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentAdi Tamar
SubjectZirconocene-Madiated Allylic C-H Bond Activation
Followed by C-C Bond Cleavage of
W-ene-Cyclopropane
DepartmentDepartment of Chemistry
Supervisor Professor Ilan Marek
Full Thesis textFull thesis text - English Version


Abstract


Metal-catalyzed cleavage of C-C and C-H bonds is a field of current interest since it can lead to the design of new, selective and efficient processes for the functionalization and utilization of ubiquitous hydrocarbons. Although the activation of C-C single bond of strained three-membered rings and allylic C-H bond are known processes, the stereoselective C-C bond activation of cyclopropanes (CP), through transition metal catalysts, have emerged only lately as an efficient tool for the synthesis of functionalized linear products.

In this context, we succeeded in developing a new method based on zirconocene-mediated ring opening of cyclopropyl ring to the synthesis of all-carbon quaternary stereocenter in acyclic systems.



It proceeds under mild condition through a sequential allylic C-H bond activation reaction followed by a selective C-C bond cleavage to give the bismetallated allyl-alkyl zirconocene  species that selectively react with two different electrophiles with high regio- and diastereoselectivity.  


We have investigated the scope and limitations of this new strategy and propose a mechanism that was corroborated by synthetic means.