Synthesis and reactivity of 1-phosphadienes and their precursors
Boyd, Bruce A.
Boyd, Bruce A.
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Date
1988
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Abstract
The sequential reaction of PCl$\sb3$ with lithium bis(trimethylsilyl)amide and 1,3-bis(trimethylsilyl)propenyllithium gives the chlorophosphine, (Me$\sb3$Si)$\sb2$NP(Cl)C(H)(SiMe$\sb3$)CH=C(H)(SiMe$\sb3$) (1). (Disilylpropenyl)phosphines, similar to 1, have been prepared with varying substituents (e.g., H, Me, t-Bu, Ph, Cl, NMe$\sb2$, N(SiMe$\sb3)\sb2$) on phosphorus by starting from either PCl$\sb3$, PhPCl$\sb2$, or Ph$\sb2$PCl. Dehydrohalogenation of several substituted allyl(chloro)phosphines, RP(Cl)C(H)(SiMe$\sb3$)CH=C(H)(SiMe$\sb3$) (R = Cl, t-Bu, (Me$\sb3$Si)$\sb2$N), was attempted with decomposition occurring for R = Cl, cyclization (DBU) or (2+2) cycloaddition (DBN) occurring for R = t-Bu, and formation of the 1-phosphadiene (Me$\sb3$Si)$\sb2$NP=C(SiMe$\sb3$)CH=C(H)(SiMe$\sb3$) (21) occurring for R = (Me$\sb3$Si)$\sb2$N. Reaction of 21 with sulfur or trimethylsilylazide gives the cyclic phosphetenes (Me$\sb3$Si)$\sb2$N(E=)P-C(SiMe$\sb3$)=CH-C(H)(SiMe$\sb3$) (27: E = S; 29: E = N(SiMe$\sb3)\sb2$). A structural isomer of 29, ((Me$\sb3$Si)$\sb2$N) (SiMe$\sb3$N=)P-C(H)=C(SiMe$\sb3$)-C(H)(SiMe$\sb3$), was prepared by treating an animo(imino)phosphorane with trimethylsilylacetylene. Reaction of the 1-phosphadiene 21 with alkyllithium reagents affords the nucleophilic/1,4-addition products R$\sb2$PC(SiMe$\sb3$)=CHC(H)(SiMe$\sb3)\sb2$ (32a,b) (R = Me, t-Bu) and their condensation analogues 33a,b which contains a linear P$\sb2$C$\sb6$ backbone. The structure of 33b was determined by X-ray spectroscopic analysis. Oxidation of the vinyl phosphines 32 by sulfur or trimethylsilylazide gave the corresponding vinyl phosphoranes. Coordination of the 1-phosphadiene was achieved by treating 21 with Mo(CO)$\sb6$. The complex was studied by X-ray spectroscopic analysis and the coordination to the metal was found to be through the phosphorus lone pair.
Contents
Subject
Subject(s)
Phosphorus
Phosphadienes
Phosphadienes
Research Projects
Organizational Units
Journal Issue
Genre
Dissertation
Description
Format
vii, 139 leaves, bound : illustrations
Department
Chemistry and Biochemistry