tag:blogger.com,1999:blog-51846086760422068.post4365156881205563569..comments2024-03-28T08:37:08.964-07:00Comments on Open Flask: An Adventure into Nickel Cross Coupling Chemistry!BaranLabhttp://www.blogger.com/profile/01806245988209508968noreply@blogger.comBlogger31125tag:blogger.com,1999:blog-51846086760422068.post-14350557719580876752018-03-29T04:16:30.574-07:002018-03-29T04:16:30.574-07:00I have been trying to set up my amateur lab for qu...I have been trying to set up my amateur lab for quite some time now, and I'm finding finances a bit difficult to come by. Any donation of any size would be greatly appreciated by a learning chemist in need.<br /><br /><a href="http://akasmedical.com/Akas-Terumax-Rx.php" rel="nofollow">syringe infusion pump</a><br /><br /><a href="http://akasmedical.com/Akas-Terumax-Rx.php" rel="nofollow">syringe pump manufacturers</a><br /><br /><a href="http://akasmedical.com/Akas-Terumax-Rx.php" rel="nofollow">syringe pump suppliers</a><br />ranahttps://www.blogger.com/profile/17602457002387034984noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-2205607911899567112016-03-31T09:13:02.245-07:002016-03-31T09:13:02.245-07:00I have been trying to set up my amateur lab for qu...I have been trying to set up my amateur lab for quite some time now, and I'm finding finances a bit difficult to come by. Any donation of any size would be greatly appreciated by a learning chemist in need.<br /><br />https://fundanything.com/en/campaigns/heating-mantle-for-home-education?col=-68710Anonymoushttps://www.blogger.com/profile/10236956552442937854noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-78630939095973411832016-02-26T12:24:29.730-08:002016-02-26T12:24:29.730-08:00Yeah, for the scale we run I think a syringe filte...Yeah, for the scale we run I think a syringe filter should be adequate. If I get some free-time I'll try a reaction and let you know!Anonymoushttps://www.blogger.com/profile/02047453150240021020noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-10799646091531202522016-02-26T12:23:15.208-08:002016-02-26T12:23:15.208-08:00Hi Milkshake,
I've definitely seen this paper...Hi Milkshake,<br /><br />I've definitely seen this paper, and we are very interested in trying something like this...Anonymoushttps://www.blogger.com/profile/02047453150240021020noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-27920793581592421172016-02-26T01:18:30.606-08:002016-02-26T01:18:30.606-08:00Hi Jacob,
thanks for the answer! Filtering the ex...Hi Jacob,<br /><br />thanks for the answer! Filtering the excess zinc from the mixture shouldn't be too much of a problem: I've done it hundreds of times (literally!), either on celite (a bit bothersome, but OK), through a filtering canula (works perfectly), or through syringe filters (ok on small scales).<br /><br />Anyway, very cool chemistry, and I look forward to any other project you might have on this kind of stuff!Anonymoushttps://www.blogger.com/profile/03909029295480888381noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-37369046103529202442016-02-21T10:10:15.744-08:002016-02-21T10:10:15.744-08:00it means that 2eq are the responsible for the reac...it means that 2eq are the responsible for the reaction. <br />its really nice work.<br />Anonymoushttps://www.blogger.com/profile/07244588864452661608noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-30665199355962025892016-02-21T02:24:19.054-08:002016-02-21T02:24:19.054-08:00Please have you seen this paper from MacMillan-Gre...Please have you seen this paper from MacMillan-Gregg Fu collaboration? pubs.acs.org/doi/pdf/10.1021/jacs.5b13211 <br /><br />Their system is pretty similar on nickel (and the bisoxazolidine ligand) and they are getting ees around 90% with photocatalytic decarboxylation of N-Boc aminoacids. If you could combine the scalability and very low cost of your system with the good ee induction that they are getting... (Blue LEDs and iridium-based photocatalysts are like a mother in law - helpful, but life is easier when there is none)milkshakehttps://www.blogger.com/profile/08188961610554710616noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-52573736453735405252016-02-20T22:35:14.941-08:002016-02-20T22:35:14.941-08:00Hi Martin,
We did try MeCN in place of DMF, and t...Hi Martin,<br /><br />We did try MeCN in place of DMF, and this resulted in much lower yields. However, we always were using a MeCN/THF mixture since we prepared the organozinc reagent in THF, so maybe if we prepared the organozinc reagent in MeCN and also ran the reaction with just MeCN (no THF) this could work. I'm not so sure how stable the activated esters will be towards zinc, however, so I think excess zinc might need to be filtered off before running the reaction. <br /><br />In regards to the second question, we are definitely interested in trying to expand the scope to this type of reactivity!Anonymoushttps://www.blogger.com/profile/02047453150240021020noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-66951943009876577942016-02-20T22:32:09.566-08:002016-02-20T22:32:09.566-08:00Hi Raju,
We tried the reaction in just THF - this...Hi Raju,<br /><br />We tried the reaction in just THF - this resulted in lower yields typically by about 20%. We never ran the reaction in just DMF because it was most convenient for us to make the organozinc species in THF, and since the reaction worked fine with this mixture of solvents, we didn't try to pump off the THF and just run the reaction with DMF.<br /><br />We use 3 equivalents of aryl zinc species because this resulted in the best yields for all substrates. In some cases we still got good yields with less aryl zinc. In particular, when we used HATU we needed a lot of aryl zinc because about 1 equiv was always quenched by the triethylammonium salt byproducts of HATU/triethylamine.Anonymoushttps://www.blogger.com/profile/02047453150240021020noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-30288902169510823772016-02-19T04:53:50.876-08:002016-02-19T04:53:50.876-08:00hey edward,myself raju
that was a realy nice work...hey edward,myself raju <br />that was a realy nice work, good breakthrough in ni chemistry,<br />i have a two question, in these reaction you have ever tried the reaction with only one solvent like either THF or DMF.<br /> I didn't gate the idea behind the using 3(eq) of Zn catalyst<br /><br /><br />Anonymoushttps://www.blogger.com/profile/07244588864452661608noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-51189122123759903102016-02-18T01:11:14.894-08:002016-02-18T01:11:14.894-08:00We haven't tried that - and I don't have a...We haven't tried that - and I don't have a good excuse not to do so, considering I have a bottle of Knochel's base on my bench...Anonymoushttps://www.blogger.com/profile/02047453150240021020noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-25237662167964047352016-02-17T03:09:48.735-08:002016-02-17T03:09:48.735-08:00Hi!
Very interesting methodology, but I have a fe...Hi!<br /><br />Very interesting methodology, but I have a few questions:<br />Did you try using another solvent instead of DMF? Actually, I'll be more specific: did you try MeCN? I've worked with C. Gosmini, and have done a lot of ArZnBr using catalytic CoBr2 and Zn in MeCN (see JACS 2003,125, 3867 or better yet Tet Lett 2003, 44, 6417), and I wonder if that methodology could be used to prepare the arylzinc for the cross-coupling. <br />Also, does the reaction work with AlkylZnX.LiCl?<br /><br />Cheers, and keep up the good work!Anonymoushttps://www.blogger.com/profile/03909029295480888381noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-53990446727548800152016-02-16T15:16:19.206-08:002016-02-16T15:16:19.206-08:00an immodest proposal: please have you tried to imp...an immodest proposal: please have you tried to improve the aryl zinc economy by adding a dummy non-transferable ligand, to form a higher-order zincate , maybe an extra equivalent of Knochel-Hauser base, or sodium-DMSO anion? milkshakehttps://www.blogger.com/profile/08188961610554710616noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-83826790248466189522016-02-14T15:57:08.684-08:002016-02-14T15:57:08.684-08:00Good question! The first hit for showing that we c...Good question! The first hit for showing that we could successfully transmetallate an organozinc reagent and have the desired reaction occur was actually performed with an old bottle of PhMgBr and some pretty wet zinc chloride. After this we started preparing them according to Knochel's procedure because it was straight forward and gave us consistent results. We actually didn't try any of the commercial aryl zinc bromides, but I would imagine that they work.Anonymoushttps://www.blogger.com/profile/02047453150240021020noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-84749277615482511732016-02-12T06:27:01.634-08:002016-02-12T06:27:01.634-08:00Hi guys,
Have you always used the Knochel-type a...Hi guys, <br /><br />Have you always used the Knochel-type arylzinc reagents (lithium chloride adducts)? Obviously, there are a lot of arylzinc bromides that are commercially available, did these also work in this type of reaction?<br /><br />Thanks!amonkeywithatypewriterhttps://www.blogger.com/profile/09723749603101629656noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-28656691550905896522016-02-10T01:57:34.921-08:002016-02-10T01:57:34.921-08:00Hey guys, what happened to your RSS feeds? They se...Hey guys, what happened to your RSS feeds? They seem to be stuck in June 2015.Алекс Жураковскийhttps://www.blogger.com/profile/03970099886944691368noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-82188031124797558012016-02-08T05:01:33.362-08:002016-02-08T05:01:33.362-08:00Me too - my RSS feed wasn't updated eitherMe too - my RSS feed wasn't updated eitherErrHumanhttps://www.blogger.com/profile/11828295585710474245noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-10427516722597228042016-02-08T03:39:05.763-08:002016-02-08T03:39:05.763-08:00I think Boc protected alpha benzyl esters of Asp, ...I think Boc protected alpha benzyl esters of Asp, Glu would be reasonable, (they are both very cheap from ChemImpex)milkshakehttps://www.blogger.com/profile/08188961610554710616noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-36706553340020838012016-02-07T11:12:04.036-08:002016-02-07T11:12:04.036-08:00Someone has to try this once we get some free time...Someone has to try this once we get some free time. That would be a nice list of substrates in a table.Anonymoushttps://www.blogger.com/profile/02047453150240021020noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-53772097502035269712016-02-07T01:08:48.235-08:002016-02-07T01:08:48.235-08:00Well, I hadn't. Maybe some of their music wil...Well, I hadn't. Maybe some of their music will have to make the lab playlist.Anonymoushttps://www.blogger.com/profile/02047453150240021020noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-40601050519719567632016-02-06T20:20:31.612-08:002016-02-06T20:20:31.612-08:00This comment has been removed by the author.Anonymoushttps://www.blogger.com/profile/02047453150240021020noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-50512106350990777562016-02-06T17:41:48.299-08:002016-02-06T17:41:48.299-08:00I didn't realize you guys were posting any mor...I didn't realize you guys were posting any more till Chemjobber linked you! Something in the RSS feed isn't working, at least for me. Anyone else have this problem? <br /><br />I also enjoy your email address, Jacob. Heard of the cheesy Irish band, Jedward? SuperScienceGrlhttps://www.blogger.com/profile/09862525669834277034noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-990556630057740552016-02-06T01:27:22.529-08:002016-02-06T01:27:22.529-08:00I like the idea and will definitely keep it in min...I like the idea and will definitely keep it in mind for this project and related ones!Anonymoushttps://www.blogger.com/profile/02047453150240021020noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-80469026600933460762016-02-05T13:02:47.771-08:002016-02-05T13:02:47.771-08:00...who knows how the zinc dies. By the way, 4A pow......who knows how the zinc dies. By the way, 4A powdered sieves that Aldrich sells already preactivated have pores big enough for CO2 to fit. Unfortunately they would also probably gobble up Li(+), exchanging it for Na(+). But they don't upset Pd(II) coordinated to pyridine ligands so it might be worth trying just to dump in some sieves powder, to see if there is any improvement. <br />Best luck with your project, it really is interesting methodology, as it's always the case with papers from your group.milkshakehttps://www.blogger.com/profile/08188961610554710616noreply@blogger.comtag:blogger.com,1999:blog-51846086760422068.post-23241615249702660242016-02-05T10:58:48.240-08:002016-02-05T10:58:48.240-08:00We never tried running the reaction under vacuum o...We never tried running the reaction under vacuum or with an Ar sparge. I never saw any carboxylation products suggesting that the aryl zinc reagent was reacting with CO2.<br /><br />In regards to the propellane idea, we haven't tried this but you could imagine some pretty interesting products from this type of reaction! We'll have to add it to the to-do list.Anonymoushttps://www.blogger.com/profile/02047453150240021020noreply@blogger.com