Chiral 2-Methyl-2-phenyl-1,3-oxazine-4,6-diones. Novel Building Blocks for the Synthesis of Enantiomerically Pure Compounds

Abstract

Synthesis and optical resolution of (Z)-5-benzylidene as well as 5-alkyl derivatives of the title compounds have been accomplished. The Diels-Alder reaction of the former with ketene diethylacetal and base-mediated methylation of the latters were found to proceed preferencially from the same side of 2-methyl group of the oxazinedione rings. The reason for this selectivity is proposed.

Reactions of 2,2,6‐Trimethyl‐1,3‐dioxin‐4‐one with the Aryl Aldimines Prepared from Thiophene‐2‐carbaldehyde

“…1,3‐Oxazin‐4‐ones are useful precursors and building blocks for the synthesis of poly‐functionalized nitrogen containing heterocycles . Alkylidene acetoacetamides are also important synthetic intermediates, in particular for intramolecular ring annulations .…”