BICYCLIC POLYPHOSPHINE POLYOXIDES ALKYLAT ED AT THE PHOSPHORUS ATOM

In the preparation of gamma and beta- tracers for use in biomedical me asurement, we have studied the reaction between two alkylated dioxopho sphides and the o-xylene-alpha,alpha'-dichloride 5. The dioxophosphide s are prepared by reaction of diisopropylethylenediphosphinate 1 or di isopropyltrimethylenediphosphinate 2 with sodium bis(methoxyethoxy)alu minohydride (vitride). The cycloaddition reactions give predominantly the 1/1 cyclocondensation compounds 6 and 9; 2/2 and 3/3 cyclocondensa tion products 7, 8, 10 are also-obtained but in significantly lower yi eld. The yield of the 1/1 product can be optimized when the reaction i s monitored by P-31 NMR. The 1/1 products are mixtures of diastereoiso mers which have been identified. The cyclic diphosphines 11 are obtain ed by reduction of the corresponding cyclic phosphine dioxides using L iAlH5-CeCl3.