Quite an entertaining read, though nothing of this olfactory caliber has happened to me (yet). I’ve only worked with tosyl chloride (nauseatingly sweet wet popcorn stench) and pivaloyl chloride (a mix of vomit and week-old garbage). Even though tosyl chloride smells horrible, the alkyl tosylate I made smelled quite pleasant.

Org Prep Daily

Beautiful asymmetric transition metal-catalysed chemistry with phosphine ligands chiral on phosphorus dates back to Knowles and Mislow. But these P-stereogenic homochiral phosphines are usualy harder to make, so they were eventually supplanted by ligands with chirality on carbon. As a freshman I used to work for a young assistant prof in Prague – and since I was very interested in asymmetric synthesis, he suggested that I could do a thesis work with him on these ligands; We would put some chiral but racemic phosphine building block onto optically active binaphtyl piece derived from BINOL, and we would get BINAP-like ligands with both axial chirality and chirality on phosphorus. We would then try to separate the stereoisomers and see which one worked better in Rh and Ru-catalysed asym hydrogenations, and we would try to interconvert the stereoisomers to see how the kinetic vs thermodynamic induction control looks like, etc. (Chiral phosphines are conformationally labile on phosphorus above 100C whereas the 2,2′-disubst binaphtyl pieces are fairly stable and should not racemize).

This all happened more than 20 years…

View original post 833 more words

Advertisements