Treatment of N,N-Dibenzylamino Alcohols with Sulfonyl Chloride Leads to Rearranged β-Chloro Amines, Precursors to β-Amino Acids, and Not to Tetrahydroisoquinolines

[reaction: see text] Very recently, the unexpected formation of 3-substituted 1,2,3,4-tetrahydroisoquinolines starting from N,N-dibenzyl-protected beta-amino alcohols was reported. The authors claimed that treatment with tosyl chlorides induced intramolecular Friedel-Crafts alkylation. Reexamination of the reactions in our laboratory clearly proved rearranged chloro amines instead of the initially assumed tetrahydoisoquinoline structures. The chloro amines investigated can be employed as highly useful intermediates for an EPC synthesis of beta-amino nitriles and beta-amino acids.