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I am trying to come up with a synthesis of 7-hydroxyspiro[4.5]decan-1-one;

Target molecule

I think I could use these starting reagents below;

Starting materials: cyclopentanone and pent-4-en-1-ol

Could I potentially generate the enolate of the cyclic ketone starting material and it would attack the double bond of the alcohol? If this is correct, how would the ring close to create the spirocycle? Thanks.

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    $\begingroup$ Enolates won't react with the C=C, it probably just deprotonates the alcohol and then sits there. $\endgroup$ – orthocresol Feb 22 '17 at 14:18
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Mesylate the alcohol, react that with the enolate, epoxidise the double bond then reform the enolate.

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A simple disconnection reveals cyclopentanone and 1,5-dibromopentan-2-ol that can be easily prepared.

To carry out this reaction, first, cyclopentanone is made into a silyl enol ether using TMS with a Lewis acid titanium(IV) chloride. The 1,5-dibromopentan-2-ol is then added and subsequently water to hydrolyse the silyl enol ether. Note the alcohol does not participate in the reaction as it is a bad leaving group compared to the bromide ion.

enter image description here

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    $\begingroup$ I may have missed something, but a single enolisation should give a single attachment only, i.e. a linear chain branching off of cyclopentanone? $\endgroup$ – Jan Feb 23 '17 at 19:12

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