Presentation Title
Investigation of the 1,3-diaza-Claisen Rearrangements in Ring Expansion of Vinyl N-heterocycles
Abstract
Electron-deficient isothioureas tethered to vinyl tertiary N-heterocycles can afford carbodiimides upon desulfurization with thiophilic metals and non-nucleophilic amine bases. Addition of the N-heterocycles to the carbodiimdes form zwitterionic spiro-cycles which then undergo zwitterionic 1,3-diaza-Claisen rearrangements to afford guanidine containing macro-cycles. Variation of the N-heterocycles and the tether lengths influences the different reactivity in the rearrangement. Solvent effect and stereoselectivity are also explored. The method provides easy access to novel guanidines that would be difficult to synthesize through conventional pathways.
Primary Faculty Mentor Name
Jose Madalengoitia
Status
Graduate
Student College
College of Arts and Sciences
Program/Major
Chemistry
Primary Research Category
Engineering & Physical Sciences
Investigation of the 1,3-diaza-Claisen Rearrangements in Ring Expansion of Vinyl N-heterocycles
Electron-deficient isothioureas tethered to vinyl tertiary N-heterocycles can afford carbodiimides upon desulfurization with thiophilic metals and non-nucleophilic amine bases. Addition of the N-heterocycles to the carbodiimdes form zwitterionic spiro-cycles which then undergo zwitterionic 1,3-diaza-Claisen rearrangements to afford guanidine containing macro-cycles. Variation of the N-heterocycles and the tether lengths influences the different reactivity in the rearrangement. Solvent effect and stereoselectivity are also explored. The method provides easy access to novel guanidines that would be difficult to synthesize through conventional pathways.