... amide is formed in situ by the addition of n-BuLi in n-hexane at 0 °C. (ii) The reaction ... The solvent volume was then reduced to incipient crystallization in vacuo, and the solution was stored at −20 °C for ... of a cyclo-2-phospha-4-sila-1,3-diazenium salt [Me 2 Si(N-t-Bu) 2 P + AlC1 4 ...