Total Synthesis of Erythronolide A by MgII‐Mediated Cycloadditions of Nitrile Oxides

A cycloaddition comes of age: The focal points of a stereoselective total synthesis of erythronolide A (see structure) are two MgII-mediated cycloadditions of nitrile oxides. Of broader significance, the strategy not only facilitates the synthesis of specific polyketide targets (i.e. natural products) but also opens up new possibilities for the preparation of non-natural analogues.