SYNTHESIS OF ONIO-SUBSTITUTED, DIONIO-SUBSTITUTED, AND TRIONIO-SUBSTITUTED PHOSPHINES - THE NUCLEOPHILIC BEHAVIOR OF DBN AND DBU TOWARD MAIN-GROUP ELECTROPHILES
1,5-Diazabicyclo[4.3.0]non-5-ene (DBN) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) react with chloro- and dichloro-phosphines leading to onio- and dionio-substituted phosphines. Similarly, onio-substituted silicon and tin derivatives are prepared; they are used as onio-substituent transfer reagents in the synthesis of a trionio-substituted phosphine.