Js. Davies et al., A MODEL REACTION FOR ASSESSING THE COUPLING AND CHIRAL EFFICIENCY OF REAGENTS IN DEPSIDE BOND FORMATION, Perkin transactions. 2, (12), 1995, pp. 2335-2339
The formation of Fmoc-L-Ala-L-Phlac-OBzl (and Fmoc-D-Ala-L-Phlac-OBzl
if there is racemisation) has been monitored by HPLC analysis for a nu
mber of coupling conditions between Fmoc-L-Ala-OH and H-Phlac-OBzl.dag
ger For this depside link formation it is revealed that CDI, DCC/DMAP
and mixed anhydride couplings gave yields near to 50%. Couplings via T
BTU, TNTU and TSTU gave lower yields. The best yields were achieved by
acid chloride (61%), urethane-N-carboxyanhydrides (80%) and by PyBroP
coupling (82%).