Reactivity study of the palladium cross-coupling synthesis of enediynes
Abstract
A reactivity study looking at various aspects of the palladium catalyzed (Sonogashira)
reaction for die synthesis of enediynes was performed. Alkynes were coupled to 1,2-
dichloro-, 1,2-dibromo- and 1,2-diiodobenzene. From this, four conclusions were drawn.
It was determined that the carbon-iodine bond is die most reactive towards coupling though
it is usually harder to obtain die second substitution in comparison to chlorine and bromine.
It was found that alkynes bearing TMS and C(CH3)20H or moderately bulky (TBDMS,
TIPS) groups couple to form disubstituted enediynes while alkynes containing THP do not.
It was determined that this palladium cross-coupling reaction does not exhibit much if any
solvent effect The order o f addition for die reaction mixture was only important if a reactive
alkyne was used. In cases such as this, the alkyne should be added last to minimize
homocoupling. Additionally, successful photochemical cyclizations were performed on three
of the four enediynes syndiesized.
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- Retrospective theses [1604]