Macro- and Spiro-heterocycles

Ligand ambivalence in pallada(platina)cyclic complexes of a rigid phosphine

“…31 P{ 1 H} NMR (CDCl 3 , 121.7 MHz) δ 30.8 ppm. 1 H NMR (CDCl 3 , 300 MHz) δ 7.76 (2H, t br, J 10.1 Hz), m),4.58 (1H,ddd,J 26.6,4.0,2.4 Hz),3.95 (1H,ddd,J 14.1,4.2,2.2 Hz), 2.63 (1H, t, J 3.9 Hz), 2.05 (1H, m), 1.88 (1H, t, J 4.0 Hz), 1.77 (1H, m), 1.60 (2H, m), 1.30 (2H, m), 0.93 (3H, s), 0.92 (3H, s), 0.91 (3H, s), 0.90 (3H, s), 0.86 (3H, s), 0.84 (3H, s), 0.54 (1H, m) ppm. 13 C DEPT NMR (CDCl 3 , 100 MHz) δ 215.0 (s, CO), 213.5 (d,J 4.0 Hz,CO),132.6 (d,J 34.3 Hz,132.4 (s,131.8 (d,J 9.8 Hz,, 129.0 (d,J 10.1 Hz,, 60.2 (s, C), 60.0 (d,J 3.2 Hz,C), 53.5 (d,J 78.8 Hz,CH),52.8 (d,J 79.3 Hz,CH),47.6 (d,J 1.5 Hz,C), 47.5 (d,J 1.7 Hz,C),46.3 (d,J 1.6 Hz,CH), 45.9 (d, J 1.6 It is noteworthy that, although the endo,endo-isomer was always obtained as the major product, small amounts of the endo,exo-form were observed occasionally; this had no bearing on the subsequent chemistry and the ultimate synthesis of phenop.…”

“…1 Unsaturated systems predominate, although a wide range of saturated systems from 3-membered phosphiranes to large-ring multiheteroatom species are known. 2 The coordination chemistry of small-ring unsaturates, especially the phospholes, has been exploited by, amongst others, Mathey, 3 Nelson 4 and Leung. 5 These workers and their groups have highlighted the rich chemistry that is possible with these heterocycles particularly for making other phosphines by controlled additions to coordinated phospholes.…”

Phenoxaphosphonium Mixed Ylides in Ring Expansion Reaction

“…Despite recent publications highlighting the synthesis and research on π-conjugated variants and chiral ligands, access to 7MPHs remains limited . Leveraging phosphorus heterocycles with smaller rings as initial substrates for the synthesis of 7MPHs is an attractive approach, achievable through ring enlargement, and several successful examples of this strategy are documented in the literature . One of the most applicable approaches to ring expansion proceeds via alkaline hydrolysis of four- and five-membered cyclic α-halomethyl- or vinyl-phosphonium salts, known as the Allen–Millar–Trippett rearrangement .…”