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TES-H, BF3.OEt2 Reductions with hydrosilanes
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Topic: TES-H, BF3.OEt2 Reductions with hydrosilanes (Read 3685 times)
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Nescafe
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TES-H, BF3.OEt2 Reductions with hydrosilanes
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on:
May 18, 2014, 01:20:31 PM »
Hello,
I was wondering if someone could help me understand the mechanism. Imagine we start with R-OH, reacting it with the reagents specified would mean that the alcohol attacks the BF3.OEt2 (strong lewis acid) yielding a good leaving group (R-OH-BF3). Next the hydride transfer (source: Et3Si-H) which kicks of HO-B(-)F3 forming R-H as the product and releases Et3Si+? Or is it more of a SN1 route where HO-BF3 leaves giving a R(+) to which the hyride transfers to?
Nescafe.
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Last Edit: May 18, 2014, 01:55:46 PM by Nescafe
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Nescafe
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Re: TES-H, BF3.OEt2 Reductions with hydrosilanes
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Reply #1 on:
May 22, 2014, 11:21:27 PM »
Any advice on this?
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orgopete
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Re: TES-H, BF3.OEt2 Reductions with hydrosilanes
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Reply #2 on:
May 23, 2014, 08:56:50 PM »
I don't know the answer. If the alcohol is tertiary, I think the reaction is SN1. I don't think triethylsilane is very nucleophilic, so I am not thinking it is going to be SN2. Does the reaction work with a primary alcohol? If not, not SN2.
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Nescafe
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Re: TES-H, BF3.OEt2 Reductions with hydrosilanes
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Reply #3 on:
May 24, 2014, 09:19:48 AM »
I see, the alcohol is secondary, it is cyclobutanol.
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orgopete
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Re: TES-H, BF3.OEt2 Reductions with hydrosilanes
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Reply #4 on:
May 24, 2014, 02:43:53 PM »
I'm still guessing SN1.
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Nescafe
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Re: TES-H, BF3.OEt2 Reductions with hydrosilanes
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Reply #5 on:
May 24, 2014, 03:17:47 PM »
Quote from: orgopete on May 24, 2014, 02:43:53 PM
I'm still guessing SN1.
Its done in ether though, I thought SN1s are typically favored in polar protic solvents to stabilize the charge of the T.S. Hmmm, but I see your point it makes sense, and SN1 does not have to be done in a polar protic solvent, i would imagine ether is sufficient to dissolve the reagents.
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TES-H, BF3.OEt2 Reductions with hydrosilanes