Use of 2,2′-Dibenzothiazolyl Disulfide-Triphenylphosphine and Lawesson’s Reagent in the Cyclization of β-Amino Acids

The disulfide reagents 2,2′-dithiobisbenzothiazole (MBTS) and 2,4-bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane 2,4-disulfide (Lawesson’s Reagent, LR) mediate the cyclization of β-amino acids with remarkable product yields. Compared to other cyclodehydrating agents, these have been found to be superior in terms of their cost, making them industrially viable. The advantageous properties of MBTS and LR make them useful and unique additions to the arsenal of cyclodehydrating agents.