Ephedrine (or pseudoephedrine) is reacted with an excess of p-toluenesulfonyl chloride to form O,N-ditosyl-ephedrine, which is reacted with an excess of lithium powder in the presence of a catalytic amount of naphtalene in THF at dry ice temperature, which exchanges the O-tosyl leaving group for a lithium ion, giving 1-lithio-N-tosylephedrine, which upon quenching with a proton donor (ammonium chloride, alcohol etc) should give N-tosyl-methamphetamine.
See
https://www.thevespiary.org/rhodium/Rhodium/pdf/alkylsulfate2alkyllithium.pdf
for the R
1O-SO
2-OR
2 -> R
1Li + R
2Li reaction.
Reflux of N-tosyl-methamphetamine with a phenol in Hydrobromic acid for 20 minutes deprotects the nitrogen, giving d-Methamphetamine in 90% yield from the sulfonamide, see
Post 339848
(Rhodium: "Sulfonamide cleavage", Novel Discourse).
