Synthesis of benzoxazinoid acetal glucosides naturally occurring in <em>Gramineae </em>

Abstract

Benzoxazinoid acetal glucosides, a unique class of natural hemiacetal ethers from <em>Gramineae </em>and other species, are of interest as precursors of aglucones which exhibit high bioactivity as plant resistance factors against microbial diseases and insects, allelo chemicals and endogeneous ligands. This review gives a survey on synthetic methods which give rise to the hemiacetalic aglucones of the 2-hydroxy-2<em>H</em>-1 ,4-benzoxazin- 3(4<em>H</em>)-one skeleton, efficiently. As a result of investigations in the area of acetal glucosidation a double diastereoselective glucosidation method of racemic cyclic hemiacetals has been developed that affords an access to the acetal glucosides of natural configuration as well as to their enantiomers.