Triphospholyl anions, formation

Treatment of the anion of 3,5-di-/-butyl-l,2,4-triphospholyl 68 with Sil4 afforded an orange cage compound 22 in 55% yield. The mechanism of formation of compound 22 is currently unknown but it seems that the first step involves an Si-P bond formation (Equation 12) <2000CC879>. 

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