:P I like, however, that they also showed ALL the failed approaches (I feel bad for the PhD'ers on in question).Read and write many popular chemical file types for working with the applications you use:ĪCD/ChemSketch Documents (.sk2), ChemDoodle Documents (.icl), ChemDoodle 3D Scenes (.ic3), ChemDoodle Javascript Data (.cwc.js), CambridgeSoft ChemDraw Exchange (.cdx), CambridgeSoft ChemDraw XML (.cdxml), Crystallographic Information Format (.cif), CHARMM CARD File (.crd), ChemAxon Marvin Document (.mrv), Chemical Markup Language (.cml), Daylight SMILES (.smi. Seems like a pretty bad synthesis strategy if it depends on that reaction to work (Scheme 18). It was like a 14 membered ringclosing reaction onto an amide (will try to find the paper).ĮDIT: This is the paper I meant: DOI: 10.1021/ja207385y Mostly, I stay away from exotic reagents, because they are often highly optimized for only a set of specific compounds, and they tend to be expensive!įor the last step I would follow /u/elnombre91 's suggestion, although I have seen a ridiculous intramolecular lithiation/barbier reaction before, when everything else they tried failed. The same issue concerns the Wittig reaction, where there are two possible product (where I'm not sure which one would form).įor the halogenation step I would suggest an easy Appel reaction. In the first step you would need propynone instead of propenone for the conjugate addition.That being said, it would produce predominantly the trans isomer. I like the idea though (and it generates discussion)! Bu3SnH works well to produce akyl-halogen radicals, but since I'm not an expert on radical reactions involving sp3 carbons I can't predict anything that makes sense. The radical reaction might certainly work, I'm just not sure if those are the right reagents for it. If anyone has any questions about any of the steps, I'd be happy to answer them. The ketone that's formed will spontaneously condense with the amine to give the desired imine. The penultimate step is a pinacol rearrangement with the alkyl group that migrates being the only one anti-periplanar to the tertiary alcohol - it migrates along the top face of the 5-membered ring to give the correct stereoconfiguration at the spiro centre. The borohydride reduction is a Narasaka reduction which gives 1,3-diols and the subsequent dihydroxylation is directed by the two hydroxy groups. The Diels Alder reaction follows the usual selectivities, giving the endo product with the absolute stereocontrol coming from the chirality of the dienophile. the ring-closing metathesis step is neccessary as forming the trans-5,5 fused ring is extremely difficult and both ring junction stereocentres need to be set before ring formation. The Evans auxiliary controls the incorporation of the isopropyl group via the boron enolate shown by the Benzyl group blocking the top face. The vinyl Grignard attacks on the opposite face to the adjacent alkyl chain. The enzymatic oxidation is just from a paper I found. I'm pretty sure all the stereocontrol is solid it was quite a tricky target. Post memes/jokes in /r/chemistrymemes and /r/chemistryjokes. Any such posts will be deleted.Īsk education and jobs questions in the current weekly topic. If you're looking for a more concentrated, advanced discussion of chemistry topics among professionals and grad students, check out /r/Chempros.īefore asking "What chemical is this?" see this chart. Click here for the OSHA chemical data site and here for a multicompany MSDS aggregate search. If you spill/injure yourself contact medical professionals and read the MSDS, do not post to this reddit. Yes links to blogs, images, videos, comics, and infographics are okay especially if they are on your personal website. No physorg, sciencedaily, or other press release aggregator spam!
DRAWING A WITTIG REAGENT IN CHEMDOODLE LICENSE
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