Hainan Cephalotaxus Lactone Synthesis Preliminary Study

In order to search for total synthesis of Hainanolide and form srven-membered cyclic ketone which was a necessary structure in Hainanolide, two methods of ring enlargement reaction were studied. 1. The method via dibromomethylcar-binol: At the base of repeating the reported method of ring enlargement reaction of monocyclic kotones via dibromome-thylcarbinols, ring enlargement reaction of 3-methyl-decahydro--2-naphthanona which was a dicyclic ketone was studied. Its ring enlargement products showed that the reaction was regiospecifical. This method was tried to synthesize many groups substituted naphthanone which was a intermediate of Hainanolide, but unsuccessfully. 2.The method via diazomethane: Reported ring enlargement reactions of simple and complex, dicyclic ketones via diazomethanenc were investigatedThis method was used to ring enlargement reaction of many groups substituted naphthanone, thereby seven -membered cyclic kctone was obtained.3-Methyl-decahydro~2-naphthanone and spiro (1,3-dioxocyclopentane)-2,6' -(3' -methyl -4' -ethyloxycarboxy-decahydro-2'-naphthanone) which were studied by ring enlargement reaction were synthesized. The ster.ic structure of later was determined. Products and side-products which were separated were identified (two unidentified), one geometrical isomer which had been infered previously was corrected by NOE different spectrum.