Concave reagents. 31 - A Merrifield bound concave pyridine for the selective acylation of polyols

The concave pyridine 2a has been synthesized in 61% yield in the two macroc yclization steps. After deprotection to give 2b, the concave pyridine has b een attached to a Merrifield resin, and the resulting polymer 10 containing 0.3 mmol 2/g has been used as a selective acylation catalyst for the addit ion of propane-1,2-diol (11) and the glucose derivative 14a to diphenylkete ne (12) to form selectively 2-hydroxypropyl diphenylacetate (13a) (selectiv ity 13a/13b: 11:1) and methyl 4,6-0-benzylidene-2-diphenylacetyl-alpha-D-gl ucopyranoside (14b), (selectivity 14b/13c: 29:1), respectively. After succe ssful applications in batch reactions, the selective addition of 11 to 12 h as also been carried out in a flow reactor filled with the polymeric cataly st 10.