Chemie und Stereochemie der Iridoide, XV. Eine effiziente Synthese enantiomerenreiner (−)‐Specionin‐Analoga aus peracetylierten Iridoidglucosiden Kristall‐ und Molekülstruktur von (−)‐3′‐Methoxyspecionin

Chemistry and Stereochemistry of Iridoids XV. – An Efficient Synthesis of Enantiomerically Pure (−)‐Specionin Analogs from Peracetylated Iridoid Glucosides. – Crystal and Molecular Structure of (−)‐3′‐Methoxyspecionin When peracetylated iridoid glucosides are submitted to hydroxymercuration and reduction with zinc the glucoside bond is cleaved exclusively. The aglycones can be regio‐ and stereoselectively transformed into specionin analogs. An example is the preparation of crystalline (−)‐3′‐methoxyspecionin ( 3b ) from hexaacetyl‐6‐ O ‐vanilloylcatalpol ( 1d ), which is readily available in larger quantities. The stereochemistry of 3b was determined by X‐ray crystallographic analysis.