Oxidative allene functionalization enables the installation of diverse heteroatoms across three
contiguous unsaturated carbons, providing rapid access to valuable intermediates for the
synthesis of natural products and active pharmaceutical ingredients (API). However, conventional
oxidation conditions often suffer from poor regioselectivity and overoxidation prompting further
development for more widespread use. In the first work, | will present our work in the development
of a TEMPO-mediated electrochemical dioxygenation of aryl allenes. Subsequent
postfunctionalization of the resulting vinyl-TEMPO intermediate enabled a sequential
trifunctionalization of the parent aryl allene. Mechanistic studies were performed using cyclic
voltammetry, computations, and in situ NMR reaction monitoring to uncover a rare outer-sphere
electron transfer-mediated oxidation. My next work extends the electrochemical flow system to
the operando NMR analysis of other electrochemical transformations such as the Shono oxidation
and electroreductive coupling enabling real-time insight into reaction optimization. Finally, my
most recent work broadens the dioxygenation strategy to alkoxyallenes. This allowed access to
TEMPO-acrolein and its derivatives, which we demonstrated to be a modular platform to install
various heterocycles over the three-carbon synthon. This approach demonstrates the synthetic
Utility of alkoxyallenes as a versatile building block to rapidly build complexity, exemplified in the
total synthesis of the natural product clathrodin.
Mechanistic Insights and Synthetic Applications of TEMPO-Mediated Allene Dioxygenation
Ken Lee