P ‐Aminophosphaalkenes with C ‐Isopropyldimethylsilyl Groups

Amination of the C ‐isopropyldimethylsilyl P ‐chlorophosphaalkene ( i PrMe 2 Si) 2 C=PCl ( 1 ) leads to the P ‐aminophosphaalkenes ( i PrMe 2 Si) 2 C=PN( R ) R ′ ( R, R ′ = Me ( 2 ), R = H, R ′ = n Pr ( 3 ), R = H, R ′ = i Pr ( 4 ), R = H, R ′ = t Bu ( 5 ), R = H, R ′ = 1‐Ada ( 6 ), R = H, R ′ = CPh 3 ( 7 ), R = H, R ′ = Ph ( 8 ), R = H, R R′ = 2,6‐ i Pr 2 Ph (= DIP) ( 10 ), R = H, R ′ = 2,4,6‐Me 3 Ph (= Mes) ( 11 ), R = H, R ′ = 2,4,6‐ t Bu 3 Ph (= Mes*)] ( 12 ), R = H, R ′ = SiMe 3 ( 13 ), and R, R ′ = SiMe 2 Ph (1 4 ). 31 P‐NMR spectra confirm that phosphaalkenes 2 – 7 and 10 – 14 are monomeric in solution; the structures of 7 , 10 , and 12 were determined by X‐ray crystallography. Freshly prepared ( i PrMe 2 Si) 2 C=PN(H)Ph ( 8 ) is a monomer that dimerizes with (N→C) proton migration within several hours to the stable diazadiphosphetidine [( i PrMe 2 Si) 2 CHPNPh] 2 ( 9 ). NMR‐scale reactions of deprotonated 5 and 13 with t Bu i PrPCl provide by P–P bond formation the P ‐phosphanyl iminophosphoranes [( i PrMe 2 Si) 2 C=]( R N=)PP t Bu( i Pr) [ R = t Bu ( 15 ), R = Me 3 Si ( 17 )]. Deprotonated 5 and Me 3 GeCl deliver by N–Ge bond formation the aminophosphaalkene ( i PrMe 2 Si) 2 C=PN( t Bu)GeMe 3 ( 20 ), which with elemental selenium 5 undergoes (N→C) proton migration to form the alkyl(imino)(seleno)phosphorane [( i PrMe 2 Si) 2 CH]( t BuN=)P=Se ( 21 ), which is a selenium‐bridged cyclic dimer in the solid state.