Abstract
N-(tert-Butyloxycarbonyl)-3-pyrroline was prepared with high purity in large scale starting from cis-1,4-dichloro-2-butene via delepine reaction and subsequent cyclization in the presence of potassium carbonate followed by N-Boc protection in methanol. Judicious selection of base and solvent led to the use of a single solvent, i.e., methanol, for cyclization as well as for N-Boc protection to render the one-pot process from compound 2 more practical and greener than the stepwise version.