Diastereoselective synthesis of (+)-pseudohygroline via proline-catalyzed alpha-hydroxylation.

A highly diastereoselective total synthesis of (+)-pseudohygroline (1) starting from D-proline is described using Wittig olefination and MacMillan-alpha-hydroxylation as key reactions. (+)-Pseudohygroline is an important molecule in alkaloid chemistry as it was prepared as part of the first chemical proof of the absolute stereochemistry of biosynthetically important (+)-hygroline (2) and (+)-hygrine (3).