Easy to follow procedures; yields not reproducible


In one of my Ph.D. projects where I was working on the total syntheses of glycosphingolipids, I followed this reference to prepare some of the intermediates. This is a very important publication in the glycolipid field since it is among the few papers that descibe the total syntheses of Plakosides. The experimental section is well written and easy to follow, however many of the yields described could not be reproduced, even after a number of attempts. For example, a hydrogenation reaction done with a propargyl alcohol has been reported as giving 96% yield. The same substrate has been used by us; also, it was highly pure. The same reactants were utilized. Our yields were usually in the 40-60%. Another reaction that the yield could not be reproduced was a cyclopropanation using dioxaborolane and an allylic alcohol. This experiement was done in our laboratory a number of times, however the yield was around 60%, compared to 96% reported in the publication. My recommendation is that the % yields should be revised by the author.  

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