Question: When 2-iodobutane is treated with a
When 2-iodobutane is treated with a variety of bases in DMSO at 50°C, the percentage of 1-butene formed among total butenes is found to be dependent on the choice of base, as seen in the chart below.
a. Identify the trend observed by comparing the basicity of the bases, and then describe the correlation between reactivity (base strength) and selectivity (specifically regioselectivity).
b. The pKa of 4-nitrophenol is 7.1. Based on the trend in the previous part of this problem, provide an estimate for the percentage of 1-butene that is expected if 2-iodobutane is treated with the conjugate base of 4-nitrophenol in DMSO at 50°C.
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% 1-BUTENE STRUCTURE OF BASE (IN TOTAL BUTENES) NAME OF BASE Potassium 7.2 benzoate OK Potassium OK 11.4 phenoxide Sodium 2,2,2- NAOCH,CF, 143 trifluoroethoxide Sodium ethoxide NaOEt 17.1
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