We describe a ten stage synthesis of an advanced intermediate for elab
oration into ergot alkaloids, from 4-carbomethoxyindole. The key step
involved an intramolecular cyclisation involving the allyl cation deri
ved from N-benzenesulphonyl, 3-(3'-methoxyprop-2'-en-1'-yl), y-2'trime
thylsilylmethyl-prop-2'-en-1'-yl)-indole.