Jacobsen HKR - The best reaction in organic chemistry?

[@nh4742]

I think there is slight mistake. At 17 the cat that is donating the Hydroxygroup, the nitrogen’s should connect directly to the cyclohexan, right?

[@CasualChemistry]

Whoops! An excellent spot - yes you are correct! A very fiddly diagram to draw and I’ve screwed that up - it doesn’t really change the structure of the key step too much though from the drawing as is (I have no easy way to edit so I’ll pin this comment)

[@CasualChemistry]

To confirm the bonds from the cyclohexane should shift along one atom to bond to the N atom of the C=N not the C of the same bond

[@benoitcsk473]

Please, don't stop making videos ! I love so much your videos

[@CasualChemistry]

🙂 I certainly have no intention to stop making videos - it's a really satisfying hobby for me, particularly when they turn out to be useful for others. I occasionally get super busy with my day job that might make releases slow down, but I really like planning out a new video so will make time to make them unless I'm super overrun.

[@theonearney205]

Great video as always (and fair play for writing out the full structure by hand!!) I would love to some a video on some of the chemistry you do or have done if you felt comfortable sharing.

[@CasualChemistry]

🙂 Thanks. The 3D perspective on those pics is not perfect but I'm not sure I have the artistry to go further than those ones lol. So a lot of the asymmetric chem videos I'm putting out there are to help me in the future talk about some of my PhD work - as a total synthesis chemist - but I figured I should have some content out there that I can refer to as "check out my video on this for a more full explanation" first. Plus it gives me a bit more practice with making videos. Things on my channel at the moment are mainly things that got me into organic chemistry properly, when I'd previously seen myself as a theoretical chemist. I feel I have to work out where the line is when talking about my own lab work for a variety of reasons. Also some of the stuff is really niche - but I guess that's what research often is. As you say, I need to work out what I'm comfortable with.

[@silizimon1293]

Very nicely explained! I once saw the jacobsens catalyst being used in a synthesis excercise, however we didnt learn about it yet. As I was googling it, I only found a mechanism, in which the jacobsens catalyst directly epoxidized an alkene. In the shown step in the exercise we had already formed the epoxide with mCPBA which left me confused. Looking back it all makes sense now

[@CasualChemistry]

🙂 thanks for the feedback and glad you found the video helpful for your learning. It’s part of the reason why I wanted to make this video specifically as the details on this reaction are quite scattered about. The stereochemical model and reaction kinetics came out a few years after the initial discovery of the reactivity.

[@copycat2508]

I want to ask why at 12:24 you say that the metal catalyst activates the nucleophile. I don't understand how increasing the acidity of the water would make the water a better nucleophile, especially when the cobalt metal would withdraw electron density from the oxygen. Thank you for the video as well. It's a great explanation. Professor Jacobsen is very nice, too,

[@CasualChemistry]

I understand this to be along the lines of essentially forming a hydroxide nucleophile that is the active species in the lowest energy transition state. Not a simple setup for sure and I didn’t deep dive in the video for the sake of clarity. If you’re interested one of the key references is below. The mechanistic explanation has become more detailed with time over the last 20 years or so in an attempt to explain why this reaction in particular has such a broad substrate scope. J. Am. Chem. Soc. 2013, 135, 41, 15595-15608 doi.org/10.1021/ja408027p

[@copycat2508]

@@CasualChemistry Thank you so much! Just an hour ago, I told Professor Jacobsen about how I learned of his HKR reaction and the person called it "The Best Reaction in Organic Chemistry." I do wonder if I should send him this video just to show him. Thanks so much! (I am a bit upset I didn't get a notification from your reply to my comment. I usually go back to your videos from time to time to help me learn more, which is how I realized you responded to my comment). I am currently an undergrad, and what advice would you give me, if any? I am a slow learner.

[@copycat2508]

For context, I am currently taking adv org and inorg

[@samira.8919]

Amazing! 🙈

[@CasualChemistry]

Thanks! 😄

[@janvisagie231]

I prefer seeing what these metal-salens or their multichiral analogues do with neat epoxides and carbon dioxide, especially in the presence of TBAX or preferably DNP-PPN salts. Edit: 1:36 What's this about scooping out white powders on the bench XDDDDD

[@CasualChemistry]

Hmm, I've just been looking more into this as it's not a chemistry that I was particularly familiar with. Some funky polymerisation stuff out there too. But the HKR is still my favourite - so operationally easy, not even much solvent or effort at any point. Plus the blood red reaction mixture is pretty cool. White powders for genuine research purposes on the bench is legit, though Me3SI should definitely not be transferred in vivo by accident or on purpose 🤣

[@janvisagie231]

​@@CasualChemistry I'm not that interested in polymer chemistry myself and I'm not too sure how useful these enantiopure polymers might be unless they have some nice optic properties. Their cyclic or nitrogen (using aziridine instead of epoxide) counterparts on the other hand are pretty interesting imo. Least I'm obsessing about this since I'm writing a project proposal on this topic in the context of the valorisation of CO2.

[@CasualChemistry]

Ok - that’s cool. There’s definitely some unexplored potential with these types of catalysts I reckon too 🙂

[@snabarq4896]

Hello dear, I need your help and I messaged you on your Facebook account

[@CasualChemistry]

I've replied on Facebook.