Chiral phosphorus(iii) triflates

N-Heterocyclic phosphenium cations: syntheses and cycloaddition reactions

“…The metrical parameters of this compound were similar to those of other saturated NHP, but in this case, there was a P-O contact of 2.1850( 14 5), 1.784(6) A ˚)29 and by Bertrand in i Pr 2 NP(OTf)(2,6-(CF 3 ) 2 C 6 H 3 ) A ˚), which as late as 2002 was the "first covalent (trifluoromethansulfonate)phosphane to be structurally characterized." 30 Although the P-O length in 1a was longer than in the above examples, it was substantially shorter than those found in analogous saturated NHP compounds such as 1b (2.4210(18) A ˚,24 vide infra) and a diaminocyclohexane derivative by Kee (2.841(5) and 2.755(5) A ˚), 13 as well as two unsaturated NHP triflates reported by Gudat 8 that were clearly ionic in the solid state and had no cationanion contacts closer than the sum of van der Waal's radii. Moreover, the 31 P{ 1 H} NMR chemical shift of 1a (d P 172.9) was considerably upfield of that of its AlCl 4…”

“…20 The NHP 1b was prepared as its trifluoromethanesulfonate salt by chloride removal from 3b using AgOTf according to the method of Baker and coworkers. 20 1 H, 13 acquired in both deuterated and non-deuterated solvent were run unlocked (referenced relative to external 85% aqueous H 3 PO 4 , d 0.00). Downfield shifts were taken as positive.…”

“…1 H NMR: d 4.17 (d, 4H, CH 2 CH 2 , 3 J PH = 5.2), 7.04 (m, 2H, Ph), 7.34 (m, 4H, Ph), 7.22 (m, 4H, Ph). 13 C{ 1 H} NMR: d 47.8 (d, 2 J CP = 10.0), 118.4 (d, 2 J CP = 14.6), 122.3, 129.5, 142.3. 31 P{ 1 H} NMR: d 172.9 (s).…”

“…1 H NMR: d 1.78 (s, 6H, CH 3 ), 3.14 (d, 4H, PCH 2, 2 J PH = 12.4), 4.19 (d, 4H, NCH 2, 3 J PH = 7.2), 7.13 (pt, 4H, Ar), 7.25 (s, 2H, Ar), 7.44 (pt, 4H, Ar). 13 C{ 1 H} NMR: d 16.4 (d, 2 J PC = 16.1), 32.7 (d, 1 J PC = 65.2), 48.7 (d, 3 J PC = 6.9), 121.5 (d, 3 J PC = 4.6), 126.3, 128.6 (d, 2 J PC = 13.8), 130.8, 137.8 (d, 3 J PC = 7.6). 31 P{ 1 H} NMR: d 86.0 (s).…”

“…1 H NMR: d 1.59 (d, 6H, CH 3 , 4 J HH = 1.2), 2.98 (dd, 4H, PCH 2 , 4 J HH = 1.2, 2 J PH = 12.0), 3.80 (s, 6H, OCH 3 ), 4.04 (d, 4H, NCH 2, 3 J PH = 7.6), 6.93 (m, 4H, Ar), 7.33 (m, 4H, Ar). 13 C{ 1 H} NMR: d 16.2 (d, 2 J PC = 15.3), 32.6 (d, 1 J PC = 67.5), 51.0 (d, 3 J PC = 9.2), 55.8, 115.9, 124.1, 126.9, 127.9 (d, 2 J PC = 12.3), 129.5 (d, 3 J PC = 6.1), 159.2. 31 P{ 1 H} NMR: d 84.0 (s).…”