Its requirement for the exact stoichiometry is emphasized in Garbrecht's original paper, in J Org Chem. I can't even remember the year he published, I think 1967. (This is why I have jabbed at your brief overview text from time to time, hoping somebody would post that part of his paper.) Some unscrupulous ruffians stole my entire chem library, and presented me with other insults. That wasn't lately, but I have had to rely a lot on memory since. Not the best thing to rely on.
Garbrecht reviewed the 4 or 5 preceding syntheses for lysergates, with their conditions and their yields, making a convincing case that his sulfur trioxide/DMF complex method was the best up until that time, but only if exact equivalents were used. (His explanation ran something like one for the lithium salt, another hangs around the indole nitrogen, and the third complexes with the carboxyl, or a similar confusion.) Now I have no doubt the POCl3 route may bee as good, or that using the more contemporary coupling agents with the cryptic acronyms might give better results. Yet this way is good enough, call it a sentimental favorite.
turning science fact into <<science fiction>>
