| Autor: |
Boylan, Amy, Nguyen, Thien S., Lundy, Brian J., Li, Jian-Yuan, Vallakati, Ravikrishna, Sundstrom, Sasha, May, Jeremy A., Preite, Marcelo Daniel |
| Předmět: |
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| Zdroj: |
Molecules; Mar2021, Vol. 26 Issue 6, p1615-1615, 1p |
| Abstrakt: |
Two key factors bear on reaction rates for the conjugate addition of alkenyl boronic acids to heteroaryl-appended enones: the proximity of inductively electron-withdrawing heteroatoms to the site of bond formation and the resonance contribution of available heteroatom lone pairs to stabilize the developing positive charge at the enone β-position. For the former, the closer the heteroatom is to the enone β-carbon, the faster the reaction. For the latter, greater resonance stabilization of the benzylic cationic charge accelerates the reaction. Thus, reaction rates are increased by the closer proximity of inductive electron-withdrawing elements, but if resonance effects are involved, then increased rates are observed with electron-donating ability. Evidence for these trends in isomeric substrates is presented, and the application of these insights has allowed for reaction conditions that provide improved reactivity with previously problematic substrates. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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