Part 7: SYNTHESIS

Answers to the synthesis problems are given below.  These answers have been selected as they are short, but there are probably other reasonable solutions.
Red arrows indicate CC bond forming reactions and blue arrows represent functional group interconversions. Note some targets have specific stereochemistry that needs to be considered.


Notes : (1) acetylide ion used to form two new C-C bond by SN2 reaction with an alkyl halide (2) alkanes and alkenes can't be deprotonated using NaNH2 - the pKas are all wrong ! (3) by using a symmetrical alkyne, a single ketone product is obtained rather than the mixture of 2 ketones if 2-hexyne had been used instead.


Notes : (1) acetylide ion used to form new C-C bond by SN2 reaction with an alkyl halide (2)  alkanes and alkenes can't be deprotonated using NaNH2 - the pKas are all wrong ! (3) dissolving metal reduction of an alkyne is used to control stereochemistry to get the trans-alkene.





Notes : (1) alkyl halides formed by radical halogenation (2) alkyl halides eliminate under basic conditions no acidic (3) use of Simmons-Smith reaction provides the right carbene for the cyclopropanation reactions. 


Notes : (1) alkyl halides formed by radical halogenation (2) alkyl halides eliminate under basic conditions not acidic (that's for alcohols) (3) use of KMnO4 or OsO4 with cyclohexene would give a cis-1,2-diol.







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