The stereoselectivity of the alkylation of the dianion of ethyl 2-hydroxy-6-methylcyclohexanecarboxylates: Control of stereochemistry at three adjacent stereogenic centers |
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Authors: | Georg Frter Wulf Günther Urs Müller |
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Institution: | Georg Fráter,Wulf Günther,Urs Müller |
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Abstract: | Yeast reduction of rac-ethyl 2-methyl-6-oxocylohexanecarboxylate (rac- 1 ) yielded selectively (+)-ethyl 2-hydroxy-6-methylcyclohexane carboxylate (+)- 2 (Scheme 1) which has been alkylated with 5-iodo-2-methylbut-2-ene by (the dianion method to furnish the 4-methylbut-3-enyl derivat 3 (Scheme 3)). NaBH4 reduction of (+)- 1 led to three hydroxy-carboxylates (?)- 2 , (+)- 5 , and (?) -6 (Scheme 4). Allylation of the dianion of (+)- 5 afforded (+)- 7 . |
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