Table 1. Percent yield of hemi-aminal ether complex when number of molecular sieves (3 Å) and presence of Brønsted acid were varied. (Concentration of 2-PA: 35 mM, DPA: 42 mM, alcohol: 175 mM and Zn(ii): 35 mM in acetonitrile).

# of sieves	Brønsted acid	% Alcohol incorporation
0	N	0
0	Y	40
2	N	0
2	Y	88
4	N	0
4	Y	90