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Topic: TMS Ketone? how to make them?  (Read 4875 times)

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Offline faust

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TMS Ketone? how to make them?
« on: October 11, 2009, 06:10:12 AM »
good morning,

I would like to make a TMS ketone (TMS-CO-R)

Is there an easiest way than : 1) R-CHO : protection with SH-CH2CH2-SH to make the diathiane. 2) BuLi / TMS 3) deprotection.

By the way, if you add a grignard reagent on a TMS ketone, do you make a Brook rearrangement?

Thanks

Offline KritikalMass

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Re: TMS Ketone? how to make them?
« Reply #1 on: October 12, 2009, 02:50:25 AM »
Howdy,

I don't have any experience with this situation but maybe you could ask the moderator to move this post to the graduate student board- you may get quicker results over there.

Offline kiwi

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Re: TMS Ketone? how to make them?
« Reply #2 on: October 12, 2009, 08:49:11 AM »
These are more usually called acyl silanes, they do undergo Brook rearrangements upon treatment with strong nucleophiles, and there seems to a couple of ways to make them. The thioacetal route looks popular, but addition of R3Si-Li to suitably derivatised carboxylic acids (acid chlorides, weinreb amides, morpholine amides) seems more direct. See for example http://www.orgsyn.org/orgsyn/prep.asp?prep=v84p0022. There is a reasonable writeup in Katritzky's Comprehensive Organic Functional Group Transformations book.

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