The lithiation and acyl transfer reactions of phosphine oxides, sulfides and boranes in the synthesis of cyclopropanes

Abstract

Phosphine oxides are lithiated much faster than phosphine sulfides and phosphine boranes. Phosphine sulfides are in turn lithiated much more readily than phosphine boranes. It was possible to trap a phosphine sulfide THF in one case which upon treatment with t-BuOK gave cyclopropane, showing that phosphine sulfides readily undergo both phosphinoyl transfer and cyclopropane ring closure just like their phosphine oxide counterparts. The obtained data show that phosphine oxides are easily lithiated and undergo phosphoryl transfer much more readily and faster than phosphine sulfides and phosphine boranes. The observations suggest that it would be possible to perform reactions involving phosphine oxides in the presence of phosphine boranes or phosphine sulfides, potentially allowing regioselective alkylation of phosphine oxides in the presence of phosphine boranes or phosphine sulfides.

Intramolecular Nucleophilic Substitution of ω-Haloalkylphosphine Derivatives

“…12 : R f 0.35 (hexane/EtOAc 6:1); 1 H NMR (500 MHz, CDCl 3 ) δ 2.28 (d, J P–H = 13.24 Hz), 7.44–7.53 (m, 6H), 7.79–7.85 (m, 4H); 13 C NMR (126 MHz, CDCl 3 ) δ 21.67 (d, J P–C = 60.0 Hz), 128.57 (d, J P–C = 11.8 Hz), 130.67 (d, J P–C = 10.0 Hz), 131.39 (d, J P–C = 2.7 Hz), 133.81 (d, J P–C = 82.7 Hz); 31 P NMR (202 MHz, CDCl 3 ) δ 35.83; GC t R = 11.66 min; GC–MS (EI, 70 eV) m / z 232 (100), 231 (70), 218 (6), 217 (46), 200 (12), 199 (14), 185 (9), 184 (6), 183 (36), 155 (10), 153 (7), 152 (12), 141 (5), 140 (8), 139 (65), 123 (23), 121 (34), 109 (6), 107 (17), 95 (5), 91 (16), 79 (8), 78 (8), 77 (35), 65 (8), 63 (23), 51 (26), 45 (6); HRMS (ESI-TOF) m / z [M + H] + calcd for C 13 H 13 PS 233.0548, found 233.0549. Analytical data are in accordance with the literature …”

“…Analytical data are in accordance with the literature. 24 Methyldiphenylphosphine-borane (13). In a flame-dried threenecked round-bottom flask (100 mL) equipped with a magnetic stir bar, argon inlet, and septum, chlorodiphenylphosphine (1.0 mL, 5.5 mmol) was dissolved in dry degassed THF (20 mL).…”

“…The ammonia was evaporated under a water pump, and the residue was diluted with chloroform (50 mL), filtered through Celite, and evaporated to dryness, yielding 0.711 g (90%) of the title compound. 31: R f 0.55 (hexane/EtOAc 6:1); 1 H NMR (500 MHz, CDCl 3 ) δ 0.37−1.24 (br, 3H), 1.48−1.78 (m, 3H), 5.07−6.09 (m, 1H), 7.37−7.61 (m, 3H), 7.61−7.82 (m, 2H); 13 100), 121 (15), 109 (85), 108 (62), 107 (31), 83 (10), 79 (12), 78 (22), 77 (18), 65 (15), 57 (12), 51 (24), 45 (12). Data are in accordance with the literature.…”

“…44: yield 1.629 g (81%); mp 78.3−79.5 °C (lit. 30 (12), 200 (M) (100), 199 (20), 185 (12), 167 (26), 166 (9), 155 (83), 153 (12), 139 (28), 138 (53), 137 (27), 123 (12), 121 (14), 109 (23), 108 (11), 107 (24), 95 (13), 94 (29), 93 (19), 92 (9), 91 (55), 79 (12), 78 (11), 77 (34), 69 (10), 65 (22), 63 (38), 62 (20), 51 (12), 47 (10), 45 (13); HRMS (ESI-TOF) m/z [M + H] + calcd for C 9 H 13 OPS 201.0497, found 201.0489. Analytical data are in accordance with the literature.…”

“…This compound was prepared according to the general procedure from methyldiphenylphosphine sulfide (12) (0.107 g, 0.48 mmol), n-BuLi (0.43 mL, 1.6 M in hexanes, 0.72 mmol), and 1-bromo-6-chlorohexane (0.101 g, 0.53 mmol) as a colorless oil. 15d: yield 0.118 g (73%); R f 0.55 (hexane/EtOAc 6:1); 1 (2.26), 315 (7), 283 (11), 220 (8), 219 (15), 218 (100), 217 (13), 199 (14), 186 (7), 185 (24), 184 (5), 183 (31), 152 (7), 141 (7), 140 (48), 139 (27), 109 (9), 108 (19), 107 (13), 77 (10), 63 (17), 55 (9), 51 (7); HRMS (ESI-TOF) m/z [M + H] + calcd for C 19 H 24 PSCl 351.1098, found 351.1097.…”