U. Luning et W. Hacker, Concave reagents. 31 - A Merrifield bound concave pyridine for the selective acylation of polyols, J PRAK CH C, 341(7), 1999, pp. 662-667
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.