Unusually Lewis basic Pro‐azaphosphatranes

Abstract

The title compounds of the type P(RNCH2CH2)3N (1, R = H; 2, R = Me; 3, R = CHz2Ph) display the unexpected basicity trend 1 < 2 < 3 with respect to protonation which forms the azaphosphatranes (4, R = H; 5, R = Me; 6, R = CH2Ph). The unusual basicity order 1 < 2 < 3 is also supported by the trend in 1JPSe values obtained for SeP(RNCH2CH2)3N (8, R = H; 9, R = CH2Ph; 10, R = Me). Deprotonation of 4 is shown to produce a variety of deprotonated derivatives which were trapped by alkylation with MeI. A favored rationale for the unusual weakness of 4 as a protonic acid (pKa in DMSO, 29.6) is an unusual stability of the axial three‐center four‐electron bond signalled by the unusually high field 31P chemical shift of this cation (—42 ppm).

Between Adamantane and Atrane: Intrabridgehead Interactions in the Cage‐Like Phosphane Related to a Novel Tris(homoadamantane) Ring System

“…The latter, in due course, might explain the alkylation and protonation behavior of CAP intermediate compared with the behavior of PTA and azaphosphatranes. Namely, pro‐azaphosphatrane P[NH(CH 2 ) 2 ] 3 N, being the strongest considered phosphane base [ V min (P)> V min (N)], is alkylated and protonated at the phosphorus atom . CAP [ V min (P)= V min (N)] exhibits less pronounced basicity for phosphorus: it undergoes selective P‐methylation whereas its protonation occurs at the nitrogen atoms (see below).…”

Reactions of P(MeNCH2CH2)3N with primary, secondary, and tertiary alkyl halides: Evidence for a solvent-enhanced dehydrohalogenation

“…After 48 hours, the reaction mixture was filtered, and the solid was washed with 2 x 1 mL of THF and dried under vacuum. The precipitate was shown to contain the cation in %a (0.35 g, 90%) identified according to its known NMR spectral properties [2]. No other product was isolated from the filtrate upon evaporation.…”

Five-Coordinate and Quasi-Five-Coordinate Phosphorus

“…Indeed the reaction was over within an hour at room temperature, but to our surprise, the azaphosphatranes 4-6 formed in virtually quantitative yield (14,15 …”