| 摘要 |
<p>PURPOSE:To obtain the subject compound which is a synthetic intermediate for 1alpha-hydroxyvitamin D derivatives in high selectivity in a short process by reacting a readily available cyclohexanone derivative with a silylacetic acid ester as raw materials in the presence of a base. CONSTITUTION:A cyclohexanone derivative of formula I (R<1> to R<3> are H or protecting group of OH; A is H, OH or protected OH) obtained from inexpensive mannitol or tartaric acid is made to react with a silylacetic acid ester of formula II (R<4> is alkyl; R<5> to R<7> are alkyl or aryl) in the presence of a base (e.g. lithium hexamethyl disilazide) to afford the objective Z-cyclohexylideneacetic acid derivative of formula III, e.g. ethyl 2-(1-ethoxyethoxy) methyl-3,4-(dimethylmethylendioxy)-5-(methoxymethoxy)cyclohexylideneac etate.</p> |
