Dolbier HW Solutions 653

Dolbier HW Solutions 653 - Oxidation of the secondary...

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requires converting the alcohol function to some suitable leaving group, followed by substitution by an appropriate nucleophile. As reported in the literature, the alcohol was converted to its corresponding p -toluenesulfonate ester and this substance was then used as the substrate in the nucleophilic substitution step to produce the desired sul f de in 76% yield. 26.25 The f rst transformation is an intramolecular aldol condensation. This reaction was carried out under conditions of base catalysis. The next step is reduction of a ketone to a secondary alcohol. Lithium aluminum hydride is suitable; it reduces carbonyl groups but leaves the double bond intact. Conversion of an alkene to a cyclopropane can be accomplished to using the Simmons Smith reagent (iodomethylzinc iodide).
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Unformatted text preview: Oxidation of the secondary alcohol to the ketone can be accomplished with any of a number of oxidizing agents. The chemists who reported this synthesis used chromic acid. H 2 CrO 4 , H 2 SO 4 H 2 O, acetone 5-Isopropylbicyclo-[3.1.0]hexan-2-ol OH 5-Isopropylbicyclo[3.1.0]hexan-2-one (89%) O CH 2 I 2 Zn(Cu) 3-Isopropyl-2-cyclopenten-1-ol OH 5-Isopropylbicyclo[3.1.0]hexan-2-ol (66%) OH 1. LiAlH 4 2. H 2 O 3-Isopropyl-2-cyclopentenone O 3-Isopropyl-2-cyclopenten-1-ol (97%) OH NaOH H 2 O, ethanol 2 H 2 O 6-Methyl-2,5-heptanedione O O (Not isolated) HO O 3-Isopropyl-2-cyclopentenone (71%) O PBr 3 NaSCH 3 OH 3-Methyl-3-buten-1-ol Br 4-Bromo-2-methyl-1-butene SCH 3 3-Methyl-3-butenyl methyl sulfide LIPIDS 747...
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This note was uploaded on 10/03/2011 for the course CHM 2210 taught by Professor Reynolds during the Fall '01 term at University of Florida.

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