Question

Chem 2200 E1/E2 Practice Problems tn 1. Predict the major produc t in each of the following reactions Ha OEt b) Br Ph 2. When 1-chloro-oox(Compound I) is treated with sodium methoxide in methanol, elimination readily occurs to give 1,2-x0oxd compound I). However, the two diastereomers of i (la and lb) each give one single isomer of il (either lla or lib) as shown below. Provide structures for la and ib as well as a mechanistic explanation for the stereopecificity. 3. Explain the formation of only one alkene in the following reaction: CH(CHs2 4. Propose a mechanism for the following reaction H'/A 5. Explain why molecule A readily undergoes E2 elimination whole molecule 8 does not undergo E2 elimination: (trans-decalin for both) 6. Provide a mechanism and explanation regarding yields:

Answer 1

EtO^cricledminus Involve in E_2 elimination, mechanism with 2 degrees - Hydrogen atom(H_1) removal doesnot involve any stearic repulsions. Where are (H_2) is attached to 3 degrees - carbon which face stearic repulsions with the base eto^cricledminus. So, only one product is possible through E_2 - elimination. Since E_2 is anti elimination first we have to keep hydrogen and Bromine atoms is opposite directions \r\n EtO^cricledminus Involve in E_2 elimination, mechanism with 2 degrees - Hydrogen atom(H_1) removal doesnot involve any stearic repulsions. Where are (H_2) is attached to 3 degrees - carbon which face stearic repulsions with the base eto^cricledminus. So, only one product is possible through E_2 - elimination. Since E_2 is anti elimination first we have to keep hydrogen and Bromine atoms is opposite directions