Bulky P-stereogenic ligands. A success story in asymmetric catalysis

Synthesis of Photochromic Phosphines by Pd‐Catalyzed Annulation Reaction of Alkynes Bearing Phosphinyl Substituent with a Silacyclopropene

“…Phosphines constitute a central class of molecules for coordination chemistry and catalysis. As ligands [1][2][3][4] or as organocatalysts, [5][6][7] the chemical modification of phosphines remains a very active area of research and their use is the subject of constant progress fueled by the most recent advances in synthetic methodology. [8][9][10][11][12] While this strategy is well known and widely studied, controlling stereoelectronic properties remotely and reversibly remains a real challenge.…”

“…NMR (CD 2 Cl 2 , 400 MHz): δ = 0.92 (s, 9H, CH 3 tBu), 1.04 (s, 9H, CH 3 tBu), 1.71 (s, 3H, CH 3 Th), 1.74 (s, 3H, CH 3 Th), 2.32 (s, 3H, CH 3 Th), 2.34 (s, 3H, CH 3 Th), 3.79 (ABq, 2H, 2 J HH = 14 Hz, 2H, P-CH 2 ), 6.25 (s, 1H, CH Th), 6.46 (d overlap with CH Th, 1H, Si-CH vinyl), 6.47 (s, 1H, CH Th), 7.36-7.46 (m, 6H, CH o/m/p-Ph ), 7.63-7.69 (m, 4H, CH o/m/p-Ph ); 13 C { 1 H} NMR (CD 2 Cl 2 , 125 MHz): δ = 14.7 (s, CH 3 Th), 14.8 (s, CH 3 Th), 15.3 (s, CH 3 Th), 15.3 (s, CH 3 Th), 19.6 (s, C tBu), 19.7 (s, C tBu), 28.7 (s, CH 3 tBu), 29.4 (s, CH 3 tBu), 35.7 (d, 1 J CP = 46.8 Hz, P-CH 2 ), 126.8 (s, CH Th), 127.4 (s, CH Th), 128.8 (d, 2 J CP = 12.0 Hz, CH o-Ph ), 128.8 (d, CP = 12.0 Hz, CH o-Ph ), 129.7 (s, C quat. Th), 131.4 (d,3 J CP = 9.0 Hz, Si-CH), 131.5 (d,4 J CP = 2.9 Hz, CH p-Ph ), 131.6 (d,4 J CP = 2.9 Hz, CH p-Ph ), 131.9 (d,3 J CP = 10.2 Hz, CH m-Ph ), 132.4 (d, 3 J CP = 10.2 Hz, CH m-Ph ), 133.6 (d, 1 J CP = 71.0 Hz, P-C ipso ), 134.5, 135.1, 135.4, 135.5 and 137.7 (s, C quat. Th), 139.5 (s, Si-C quat.…”

“…NMR (CD 2 Cl 2 , 400 MHz): δ = 1.04 (s, 9H, CH 3 tBu), 1.14 (s, 9H, CH 3 tBu), 1.69 (s, 3H, CH 3 Th), 1.69 (s, 3H, CH 3 Th), 2.14 (s, 3H, CH 3 Th), 2.37 (s, 3H, CH 3 Th), 5.82 (d, J HH < 1.0 Hz, 1H, CH Th), 6.11 (s with29 Si sat 2. J HSi = 11.0 Hz, 1H, Si-CH), 6.59 (d, J HH < 1.0 Hz, 1H, CH Th), 7.12 (d,3 J HH = 14.2 Hz, 1H, CH o/m/p-Ph ), 7.27-7.33 (m, 2H, CH o/m/p-Ph ), 7.40-7.62 (m, 11H, CH o/m/p-Ph ); 13 C{ 1 H} NMR (CD 2 Cl 2 , 100 MHz): δ = 14.5 (s, CH 3 Th), 14.5 (s, CH 3 Th), 15.2 (s, CH 3 Th), 15.3 (s, CH 3 Th), 19.9 (s, C tBu), 20.0 (s, C tBu), 28.8 (s, CH 3 tBu), 29.3 (s, CH 3 tBu), 126.9 (s, CH Th), 127.6 (s, CH Th), 128.3 (d, 2 J CP = 12.9 Hz, CH o-Ph ), 128.7 (d, 3 J CP = 4.8 Hz, CH m-Ph ), 128.9 (d, 3 J CP = 4.7 Hz, CH m-Ph ), 130.2 (s, C quat. Th), 130.9 (s, Si-CH), 130.9 (s, CH p-Ph ), 131.0 (s, C quat.…”

“…NMR (CD 2 Cl 2 , 400 MHz): δ = 1.05 (s, 18H, CH 3 tBu), 1.67 (s, 3H, CH 3 Th), 1.87 (s, 3H, CH 3 Th), 2.23 (s, 3H, CH 3 Th), 2.38 (s, 3H, CH 3 Th), 6.07 (s, 1H, CH Th), 6.65 (s, 1H, CH Th), 7.80 (d with29 Si sat 3. J HSi = 12.0 Hz,3 J HP = 12.5 Hz, 1H, Si-CH), 7.33-7.45 (m, 10H, CH o/m/p-Ph ); 13 C { 1 H} NMR (CD 2 Cl 2 , 100 MHz): δ = 14.2 (s, CH 3 Th), 14.7 (s, CH 3 Th), 15.1 (s, CH 3 Th), 15.4 (s, CH 3 Th), 20.2 (s, C tBu), 29.2 (s, CH 3 tBu), 126.7 (s, CH Th), 126.8 (s, CH Th), 128.7 (d, 3 J CP = 6.4 Hz, CH m-Ph ), 129.0 (s, CH p-Ph ), 130.5 and 133.5 (s, C quat. Th), 134.6 (d, 2 J CP = 20.1 Hz, CH o-Ph ), 135.4, 135.4, 137.5 and 137.8 (s, C quat.…”

Unexpected rapid P-stereomutation of phosphine oxides catalysed by chlorophosphonium salts

“…30–40 kcal mol −1 , 5 making them valuable scaffolds for the design of stereoselective systems. 6 Little is known however about potentially detrimental to these methodologies catalytic stereomutation of the P -center leading to racemisation. A few very recent reports indicate that such reactions, for example acid-catalysed and SET-facilitated processes, do occur under certain conditions.…”