Diethyl Ether → Nalpha-(3-(beta-D-Galactopyranosyl)cyclohept-1-yl)-L-leucine

Participants

Reaction Steps

Step A--Synthesis of Cycloheptan-1-on-3-yl 2,3,4,6-Tetra-O-benzoyl-β-D-galactopyranoside: O-(2,3,4,6-tetra-O-benzoyl-β-galactopyranosyl) trichloroacetimidate (578 mg, 780 μmol) and 3-hydroxycycloheptan-1-one (100 mg, 780 μmol) (which was prepared in two steps from cyclohept-2-en-1-one by the procedures of E. Hasegawa8 and H. Paulson9 were dissolved in dry diethyl ether (10 mL). Trimethyl trifluoromethanesulfonate (TMSOTf) (300 μmL, 0.1M) is added at room temperature. After 1 h, the reaction is quenched with triethylamine (100 μmol) and the mixture is concentrated. Column chromatography (SiO2, toluene/ethyl acetate 16:1 to 10:1) gives the title compound (385 mg, 70%) as a white foam.

Provenance & Evidence