Problem set 4 – Chem. 127/227, Fall 2007 1. The magnitude of the beta hyperfine coupling constant for the cyclopropylcarbinyl radical suggests that the time-averaged preferred conformation is that shown below. Provide a suitable rationale for this observation given what you know about the ‘banana bond’ framework for cyclopropane. H H 2. (a) You’ve heard the term “carbinyl” used many times. What does it mean? (b) Identify the carbinyl carbon in 2-butanol. (c) Illustrate the cyclopropylcarbinyl carbenium ion. (Use your textbook to learn of the difference between the terms carbocation, cation, and carbenium ion). (d) Which conformation of the cyclopropylcarbinyl carbenium ion do you think is the more stable? How does that compare with the preference expressed by the corresponding radical? (e) Provide a rationale for your response to part ‘d’. (f) Has the cyclopropylcarbinyl carbenium ion been “synthesized” and studied? How was it studied, i.e. what techniques were used to investigate its properties? What
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This note was uploaded on 10/15/2010 for the course CHEM chem 127 taught by Professor Littlerd during the Fall '09 term at UCSB.