Concise synthesis of C2-symmetrical 2,6-disubstituted morpholines by N ® O Boc migration under SL-PTC conditions.

A novel, straightforward synthesis of enantiomerically pure 2,6-disubstituted morpholines e. g., I has been developed. The ring-opening of epoxides with TsNHBoc under solid-liq. phase transfer catalysis conditions occurred with N-->O migration of the Boc group, affording an intermediate carbonate that has been easily transformed to morpholines.