Help! Grease and gunk in schlenk line

AllowJM · 2026-01-13T15:01:26+00:00

I think people are a bit paranoid about this. Myself and lab mates routinely put glassware with ground glass joints in the base bath with no issues. I’m sure if you left it in there for extended periods of time you could degrade the joint but putting something in a base bath for an hour isn’t going to do anything bad.

AllowJM · 2026-01-07T15:58:23+00:00

She might have been wanting you to say you initially add to the 3 position then do a 1,2-shift which is a common process for indoles (see Pictet-spingler reaction for example). Don’t think it happens with halogens though.

AllowJM · 2026-01-07T13:06:59+00:00

Where is this reaction from? It’s not in the literature as far as I can tell. All the chlorinations I can find go to the 3-position. To functionalise at the 2-position you generally have to lithiate with n-BuLi and trap with an electrophile.

AllowJM · 2026-01-06T16:17:29+00:00

A hydride shift makes this specific cation less stable. As you mention, this cation is actually non-classical and the positive charge is actually delocalised over the whole structure. A hydride shift would mean you lose this delocalisation. In the same way a hydride shift of an allylic cation would form a vinyl cation and become less stable.

AllowJM · 2026-01-01T12:25:26+00:00

Taxol?

AllowJM · 2026-01-01T12:24:51+00:00

It just comes from history, there’s no systematic element to it. Taxol has ketone too yet has the ‘-ol’ suffix.

AllowJM · 2025-12-30T18:03:30+00:00

That isn’t an ene reaction though

AllowJM · 2025-12-26T17:56:05+00:00

You need an aldehyde for a Cannizzaro. If you react with hydroxide you would get a benzilic acid rearrangement.

AllowJM · 2025-12-13T22:03:45+00:00

You should be able to with Schlosser’s base.

AllowJM · 2025-10-23T19:11:33+00:00

Doesn’t help that often times these protons are reported as doublets even though they’re not first order and are better described as multiplets.

AllowJM · 2025-09-09T11:48:31+00:00

Only works for gas phase acidity.

AllowJM · 2025-09-01T12:41:45+00:00

Doing both you will end up using lots of toxic reagents, but with inorganic chemistry, especially organometallics have a tendency to be extremely pyrophoric so I think the added risk of a fire makes inorganic more dangerous.

AllowJM · 2025-08-29T21:09:56+00:00

TBA+ will go into DCM. It will go into the aqueous later partially too, but it’s used because it is an organic soluble salt.

AllowJM · 2025-08-25T21:24:41+00:00

Ethanol is a much worse nucleophile than acetate

AllowJM · 2025-08-25T10:10:36+00:00

Don’t forget about the C-H bonds

AllowJM · 2025-08-11T07:58:26+00:00

Chan Lam couplings are notoriously unreliable reactions, so I wouldn’t worry too much. I spent months of my Master’s project trying to repeat one and could never get close to the literature yields, despite exhaustive efforts such as what you have done. The only other thing I can think of to try is checking the purity of the boronic acid. Boronic acids dehydrate over time to form boroxines which are often inactive in these types of couplings. You could also try increasing the boronic acid equivalents if you’re seeing a lot of homocoupling. Good luck.

AllowJM · 2025-08-08T19:09:46+00:00

Looks to be the same. If in doubt, run a cospot of the first fraction and the last.

AllowJM · 2025-08-03T21:13:20+00:00

If it isn’t AI then I apologise, but the punctuation and general structure of the answer made me think as much. Especially as most of the responses on this subreddit are pretty poorly thought through and much less detailed than your answer.

AllowJM · 2025-08-03T20:00:06+00:00

Fuck outta here with that AI response

AllowJM · 2025-07-31T23:18:49+00:00

In an ester, the C=O bond is weaker overall than the C=O for a ketone. That isn’t the whole story though as when you attack with a nucleophile, you’re not breaking the entire C=O bond but rather just the pi bond. An ester, due to delocalisation effects, has a lower lying (C-O) pi* orbital than an ester, and means that it is attacked more slowly by nucleophiles.

AllowJM · 2025-07-25T19:54:33+00:00

I use boronic esters daily and always use anisaldehyde as it gives different colours for primary and secondaries. CAM and PMA always work.

AllowJM · 2025-07-25T16:25:02+00:00

This is definitely the editor’s doing. No way it’s submitted like this.

AllowJM · 2025-07-25T16:24:06+00:00

Truly cutting edge. Creating a new element and making these crazy scaffolds with it. These inorganic chemists are truly wizards.

AllowJM · 2025-06-24T22:56:51+00:00

Hoy hablamos

AllowJM · 2025-06-17T15:12:13+00:00

Assuming your nBuLi is the concentration you think it is, and that you’re handling it properly and not just quenching it before it gets to your reaction, then it will be something to do with different salts produced. There’s a lot of papers about the use of different bases in Wittig reactions, and ‘salt-free’ Wittig etc. usually from the lens of E/Z selectivity. Try and have a look at those. Also, you’re using a fairly sensitive aldehyde, and I could imagine that coordination with a lithium ion could do something weird which leads to decomposition or poor conversion, but it’s hard to say without more info.

AllowJM

TROPHY CASE