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Published on: February 15, 2016
Light-Induced Reactions of Diazotetrahydrofuranone without Elimination of Nitrogen: Experimental and Mechanistic
Liudmila L Rodina1, Victor I Baranovskii1, Olesia S Galkina1
1Institute of Chemistry, Saint-Petersburg State University , Universitetskii prospect 26, St. Petersburg, Petergof 198504, Russia.
Abstract:
The energies and lifetimes of the excited states (S1, S2, S5, T1) of a diazotetrahydrofuranone were determined using experimental and computational methods. It was shown that direction of the diazoketone photochemical transformations without elimination of nitrogen is determined by multiplicity and energy of the excited state, generated by UV irradiation of diazo compound: isomerization to α-ketodiazirine proceeds from the singlet S1 state, whereas the alternative process of C-H insertion with hydrazone formation occurs through the triplet T1 state. The most probable excited state that leads to elimination of nitrogen and Wolff rearrangement is one of the highest singlet excited states of diazotetrahydrofuranone.
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Rate-Determining Steps
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to...

