Mechanism for hydrolysis of enol ether to aldehyde
From what I can tell, you are having more trouble with the acidic hydrolysis of an enol ether to an aldehyde. As has been pointed out by some comments, your proposed mechanism is not really possible. Vinyl $\mathrm{sp^2}$ cations are very unstable and an $\mathrm{S_N1}$-type dissociation of MeOH is very unlikely. 1
organic chemistry - Mechanism of enolether formation with ethyl ...
2015年4月13日 · Some argue that the reaction actually proceeds through the ketal (rather than the hemiketal) since ketals can be isolated in these reactions. Others argue that just because the ketal is formed, doesn't prove it is actually involved in the enol ether formation reaction. IMO, lacking definitive evidence, I opt for the simpler hemiketal mechanism.
Mechanism of enol ether formation - Chemistry Stack Exchange
2015年6月1日 · Mechanism of enol ether formation. I assumed the the TsOH T s O H would dissociated to produce hydronium ions that would protonate the carbonyl. This would make the carbon more delta + and so susceptible to attack by MeOH M e O H. After proton exchange I thought the HX2O H X 2 O group would leave and we would have a carbocation left over.
Mechanism of a cyclization reaction - why does an enol ether form?
2017年3月10日 · That intermediate explains the need for aqueous $\ce{H+}$. Similarly to how the intermediate shown in the question wouldn't be my first guess (or, apparently, yours), I'm guessing the authors of whatever paper it's from didn't expect it, either. Luckily, the enol ether is easy enough to hydrolyze. $\endgroup$ –
Role of NaI in Formation of Silyl Enol Ethers using Chloro …
2019年4月26日 · I am forming silyl enol ethers using Chloro(trimethyl)silane (TMSCl), and below is an experimental protocol I am following. Silyl Enol Ether Synthesis. In an oven-dried 100 mL three-necked flask, Et3N (37.2 mmol) and carbonyls (30.0 mmol) were added.
By what mechanism do acids deprotect primary silyl ethers?
2015年10月7日 · Scheme 1: Selective deprotection of a primary silyl ether [1] Numerous other examples can be found in the literature using numerous acidic reagents such as campher sulphonic acid, [2] para-tolylsulphonic acid [3] and even acetic acid [4] or $\ce{HCl}$. [5] Similar conditions can be used in the case of TIPS ethers. [citations needed]
organic chemistry - Mechanism for reaction of enol ether with HBr ...
2018年4月25日 · The answer to the question had given product of mechanism 2 as major product. But I don't know if it is really correct or not. The last s step in Mech. 2 is reversible allowing liberate bromide to participate in Mech. 1. In Mech. 1 the cation in the upper right may undergo SN2 vs. SN1 reaction with bromide. In all, you did well! @user55119 Thanks!
organic chemistry - Why cyclohexane-1,4-dicarbaldehyde does …
2018年10月23日 · There are also plenty of examples where the silyl enol ether of CyCHO reacts with π-electrophiles. Silyl enol ethers are weaker nucleophiles than lithium enolates, so generally Lewis acid catalysis is required to form more powerful electrophiles. Still, these are considered to be aldol-type reactions (specifically Mukaiyama aldols).
reaction mechanism - Acid hydrolysis of Birch-reduced Anisole ...
2022年4月15日 · Enol ether 2 is the Birch reduction product of anisole (1). Protonation of the more electron-rich double bond affords species 3, which suffers attack by water at carbonyl carbon not at the methyl group, giving rise to the hemiketal 4. This species is a typical intermediate in the formation of acetals and ketals in acid medium when alcohol is ...
Products of the reaction between ethoxyethene and HI
2021年4月29日 · $\begingroup$ The substrate is an enol ether, which is very sensitive to acid. And HI is a very strong acid, which can cleave usually stable normal ether linkages. $\endgroup$ – Mathew Mahindaratne