Dolbier HW Solutions 203

Dolbier HW Solutions 203 - f gu-ration at the stereogenic...

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( f ) First convert tert -butyl chloride into an isobutyl halide. Treating isobutyl bromide with sodium iodide in acetone converts it to isobutyl iodide. A second approach is by way of isobutyl alcohol. Isobutyl alcohol is then converted to its p -toluenesulfonate ester, which reacts with sodium iodide in acetone in a manner analogous to that of isobutyl bromide. ( g ) First introduce a leaving group into the molecule by converting isopropyl alcohol to an iso- propyl halide. Then convert the resulting isopropyl halide to isopropyl azide by a nucleophilic substitution reaction ( h ) In this synthesis 1-propanol must be f rst converted to an isopropyl halide. After an isopropyl halide has been obtained, it can be treated with sodium azide as in part ( g ). ( i ) First write out the structure of the starting material and of the product so as to determine their relationship in three dimensions. The hydroxyl group must be replaced by azide with inversion of con f guration. First, however, a leaving group must be introduced, and it must be introduced in such a way that the con
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Unformatted text preview: f gu-ration at the stereogenic center is not altered. The best way to do this is to convert ( R )-sec-butyl alcohol to its corresponding p-toluenesulfonate ester. C OH H CH 3 CH 2 CH 2 ( R )-sec-Butyl alcohol ( R )-sec-Butyl p-toluenesulfonate p-toluenesulfonyl chloride pyridine C OS O O CH 3 H CH 3 CH 3 CH 2 C OH H CH 3 CH 3 CH 2 N 3 H CH 3 CH 2 CH 3 C ( R )-sec-Butyl alcohol ( S )-sec-Butyl azide H 2 SO 4 heat HBr 1-Propanol CH 3 CH 2 CH 2 OH Propene CH 3 CH CH 2 Isopropyl bromide CH 3 CHCH 3 Br HBr NaN 3 Isopropyl alcohol CH 3 CHCH 3 OH Isopropyl bromide CH 3 CHCH 3 Br Isopropyl azide CH 3 CHCH 3 N 3 tert-Butyl chloride (CH 3 ) 3 CCl Isobutyl alcohol (CH 3 ) 2 CHCH 2 OH NaOCH 3 1. B 2 H 6 2. H 2 O 2 , HO 2 2-Methylpropene (CH 3 ) 2 C CH 2 Isobutyl bromide (CH 3 ) 2 CHCH 2 Br Isobutyl iodide (CH 3 ) 2 CHCH 2 I NaI acetone tert-Butyl chloride (CH 3 ) 3 CCl Isobutyl bromide (CH 3 ) 2 CHCH 2 Br NaOCH 3 HBr peroxides 2-Methylpropene (CH 3 ) 2 C CH 2 NUCLEOPHILIC SUBSTITUTION 197...
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This note was uploaded on 09/26/2011 for the course CHM 2210 taught by Professor Reynolds during the Fall '01 term at University of Florida.

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