Stereoselective synthesis of the Halaven C14-C26 fragment from D-quinic acid: crystallization-induced diastereoselective transformation of an α-methyl nitrile.

Crystallization-induced diastereoselective transformation (CIDT) of an a-methyl nitrile completes an entirely non-chromatographic synthesis of the halichondrin B C14-C26 stereochemical array. The requisite a-methyl nitrile substrate is derived from D-quinic acid through a series of substrate-controlled stereoselective reactions via a number of crystalline intermediates that benefit from a rigid polycyclic template. Therefore, all four stereogenic centers in the Halaven C14-C26 fragment were derived from the single chiral source D-quinic acid.