Stannylated Allylsulfones as Versatile New Building Blocks

Abstract

Propargylic sulfones undergo regioselective hydrostannation in the presence of Mo(CO)₃(CNt-Bu)₃(MoBl₃), giving rise to stannylated allyl sulfones. These are interesting building blocks, because in the first step the vinylstannane subunit can be modified via Stille coupling, and in the second step the sulfone can be subjected to a Julia-Lythgoe olefination. In principle, modifications at the double bond should also be possible after the Stille coupling.

hydrostannation - Julia-Lythgoe olefination - Stille ­coupling - sulfones

References

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11

Synthesis of (1-Benzenesulfonylmethylvinyl)tributyl-stannane (1).
A mixture of phenylpropargylsulfone (270 mg, 1.50 mmol), Mo(CO)_{3 (}CNt-Bu)₃ (32.0 mg, 74.5 µmol) and Bu₃SnH (495 mg, 1.70 mmol) were solved in dry THF (5 mL) in a flame-dried flask and closed under dry argon atmosphere. The solution was then heated in the microwave oven (CEM Discover) for 17 min at 150 W. After cooling to r.t. the solvent was evaporated and the residue purified by chromatography (hexanes-EtOAc, 9:1) to give 1 (422 mg, 0.90 mmol) as a colorless oil.
Spectroscopic data of 1: ¹H NMR (300 MHz, CDCl₃): δ = 0.87-1.06 (m, 15 H, 9-H, 11-H), 1.28-1.35 (m, 6 H, 10-H), 1.46-1.54 (m, 6 H, 8-H), 3.91 (s, J _5,Sn = 19.9 Hz, 2 H, 5-H), 5.41 (d, J _{7 cis ,5} = 1.9 Hz, J _{7 cis ,Sn} = 25.7 Hz, 1 H, 7-H _cis ), 5.60 (d, J _{7 trans ,5} = 1.25 Hz, J _{7 trans ,Sn} = 56.7 Hz, 1 H, 7-H _trans ), 7.51 (dd, J _3,2 = 7.7 Hz, J _3,4 = 7.7 Hz, 2 H, 3-H), 7.60 (t, J _4,3 = 7.6 Hz, 1 H, 4-H), 7.81 (d, J _2,3 = 7.25 Hz, 2 H, 2-H). ¹³C NMR (125 MHz, CDCl₃): δ = 10.4 (3 t, J _8,Sn = 172.1 Hz, C-8), 13.7 (3 q, C-11), 27.3 (3 t, J _9,Sn = 30.0 Hz, C-9), 28.9 (3 t, J _10,Sn = 9.9 Hz, C-10), 66.3 (t, C-5), 128.5 (2 d, C-2), 128.8 (2 d, C-3), 133.4 (d, C-4), 135.9 (s, C-1), 138.6 (t, C-7), 141.4 (s, C-6).

12

Synthesis of (2-Benzylprop-2-enyl)phenylsulfone (5).
A mixture of vinylstannane 1 (235 mg, 0.50 mmol) and benzylbromide (231 mg, 1.35 mmol) was solved in dry THF (3 mL) in a Schlenk flask under argon. A solution of allyl palladium chloride dimer (3.7 mg, 10.1 µmol) and PPh₃ (5.3 mg, 20.2 µmol) was added in THF (2 mL) and the mixture was warmed to 60 °C overnight. After cooling to r.t. the solvent was evaporated and the residue purified by chromatography (hexanes-EtOAc, 9:1) to give 5 (135 mg, 0.50 mmol) as a white solid, mp 63-65 °C.
Spectroscopic data of 5: ¹H NMR (300 MHz, CDCl₃): δ = 3.49 (s, 2 H, 8-H), 3.67 (s, 2 H, 5-H), 4.82 (s, 1 H, 7-H_a), 5.05 (d, J _7b,5 = 1.0 Hz, 1 H, 7-H_b), 7.12 (d, J _10,11 = 7.3 Hz, 2 H, 10-H), 7.20 (t, J _12,11 = 7.4 Hz, 1 H, 12-H), 7.27 (dd, J _11,10 = 7.4 Hz, J _11,12 = 7.4 Hz, 2 H, 11-H), 7.54 (dd, J _3,2 = 7.9 Hz, J _3,4 = 7.9 Hz, 2 H, 3-H), 7.64 (tt, J _4,3 = 7.4 Hz, J _4.2 = 0.9 Hz, 1 H, 4-H), 7.88 (dd, J _2,3 = 7.3 Hz, J _2,4 = 1.3 Hz, 2 H, 2-H). ¹³C NMR (125 MHz, CDCl₃): δ = 42.2 (t, C-8), 61.6 (t, C-5), 121.5 (t, C-7), 126.6 (d, C-12), 128.5, 128.6, 129.0, 129.2 (4 × 2 d, C-2, C-3, C-10, C-11), 133.7 (d, C-4), 136.8 (d, C-9), 137.9 (d, C-6), 138.4 (s, C-1).

13

Spectroscopic data of 6a: ¹H NMR (300 MHz, CDCl₃): δ = 2.45 (d, J _8a,8b = 15.8 Hz, 1 H, 8-H_a), 2.73 (d, J _8b,8a = 15.8 Hz, 1 H, 8-H_b), 3.70 (d, J _5,13 = 1.9 Hz, 1 H, 5-H), 5.06 (s, 1 H, 7-H_a), 5.73 (d, J _13,5 = 2.2 Hz, 1 H, 13-H), 5.79 (s, 1 H, 7-H_b), 6.48 (d, J _15,16 = 7.0 Hz, 2 H, 15-H), 7.03-7.10 (m, 3 H, C-16, C-17), 7.24-7.31 (m, 5 H, C-10, C-11, C-12), 7.48 (ddd, J _3,2 = 7.9 Hz, J _3,4 = 7.9 Hz, J _{3,3 ′} = 1.9 Hz, 2 H, 3-H), 7.63 (tt, J _4,3 = 8.0 Hz, J _4,2 = 1.2 Hz, 1 H, 4-H), 7.73 (dd, J _2,3 = 8.4 Hz, J _2,4 = 1.1 Hz, 2 H, 2-H). ¹³C NMR (125 MHz, CDCl₃): δ = 45.1 (t, C-8), 70.1 (d, C-13), 72.9 (d, C-5), 121.6 (t, C-7), 126.0, 128.3, 128.3, 129.0, 129.0, 129.3 (6 × 2 d, C-2, C-3, C-10, C-11, C-12, C-15, C-16, C-17), 126.2 (d, C-17), 127.9 (d, C-12), 133.8 (C-4), 135.9, 136.8, 137.8 (3s, C-1, C-9, C-14), 139.3 (s, C-6).
Spectroscopic data of 6s: ¹H NMR (300 MHz, CDCl₃): δ = 2.45 (d, J _8a,8b = 16.1 Hz, 1 H, 8-H_a), 2.65 (d, J _8b,8a = 16.1 Hz, 1 H, 8-H_b), 3.93 (d, J _5,13 = 9.5 Hz, 1 H, 5-H), 4.27 (s, 1 H, OH), 4.67 (s, 1 H, 7-H_a), 5.22 (s, 1 H, 7-H_b), 5.37 (d, J _13,5 = 9.5 Hz, 1 H, 13-H), 6.35 (dd, J _15,16 = 6.6 Hz, J _15,17 = 1.6 Hz, 2 H, 15-H), 7.02-7.09 (m, 3 H, 16-H, 17-H), 7.24-7.28 (m, 5 H, C-10, C-11, C-12), 7.53 (ddd, J _3,2 = 7.9 Hz, J _3,4 = 7.9 Hz, J _{3,3 ′} = 1.6 Hz, 2 H, 3-H), 7.66 (tt, J _4,3 = 6.0 Hz, J _4,2 = 1.1 Hz, 1 H, 4-H), 7.85 (dd, J _2,3 = 7.3 Hz, J _2,4 = 1.1 Hz, 2 H, 2-H). ¹³C NMR (125 MHz, CDCl₃): δ = 43.8 (t, C-8), 74.4 (d, C-13), 75.0 (d, C-5), 120.5 (t, C-7), 126.3 (2 d, C-17), 127.9, 128.2, 128.3 (3 × 2 d, C-10, C-11, C-16), 128.4 (d, C-12), 128.9 (2 d, C-3), 129.4 (2 d, C-15), 129.5 (2 d, C-2), 134.0 (C-4), 136.4, 137.8, 139.2 (3 s, C-1, C-9, C-14), 139.5 (s, C-6). Anal. Calcd for C₂₃H₂₂O₃S (378.49): C, 72.99; H, 5.86. Found: C, 72.89; H, 5.96.

14

Preparation of Compounds 7s/8.
A solution of sulfone 5 (135 mg, 0.50 mmol) in THF (3 mL) was cooled to -40 °C before 1.6 M BuLi (0.32 mL, 0.51 mmol) was added. The mixture was stirred for 30 min, the cooling bath was removed for 3 min, and after cooling again to -40 °C fresh distilled benzaldehyde (60 mg, 0.56 mmol) was added. After stirring for further 30 min at this temperature, CS₂ (95 mg, 0.125 mmol) was added, and the mixture was allowed to warm to -20 °C during 2 h. After cooling to -40 °C MeI (210 mg, 1.5 mmol) was added and during 2 h the mixture was warmed to r.t. The solvent was evaporated in vacuo and the residue purified by chromatography (hexanes-EtOAc, 9:1) giving rise to 7s (140 mg, 0.30 mmol, 60%) as a colourless solid, mp 148-149 °C. Compound 8 was obtained as minor product (50 mg, 0.13 mmol, 26%) as a colourless oil.
Spectroscopic data of 7s: ¹H NMR (300 MHz, CDCl₃): δ = 2.38 (s, 3 H, 19-H), 2.92 (d, J _8a,8b = 16.1 Hz, 1 H, 8-H_a), 2.98 (d, J _8b,8a = 16.1 Hz, 1 H, 8-H_b), 4.37 (d, J _5,13 = 10.1 Hz, 1 H, 5-H), 4.95 (s, 1 H, 7-H_a), 5.47 (s, 1 H, 7-H_b), 6.60 (ddd, J _15,16 = 7.6 Hz, J _15,17 = 1.9 Hz, J _{15,15 ′} = 1.9 Hz, 2 H, 15-H), 7.04 (d, J _13,5 = 10.4 Hz, 1 H, 13-H), 7.12-7.17, 7.20-7.26 (2 m, 8 H, H-10, H-11, H-12, H-16, H-17), 7.52 (ddd, J _3,2 = 7.7 Hz, J _3,4 = 7.7 Hz, J _{3,3 ′} = 1.6 Hz, 2 H, 3-H), 7.62 (tt, J _4,3 = 7.6 Hz, J _4,2 = 1.4 Hz, 1 H, 4-H), 7.82 (ddd, J _2,3 = 7.9 Hz, J _2,4 = 1.3 Hz, J _{2,2 ′} = 1.3 Hz, 2 H, 2-H). ¹³C NMR (125 MHz, CDCl₃): δ = 19.0 (q, C-19), 44.4 (t, C-8), 72.0 (d, C-5), 82.6 (d, C-13), 121.5 (t, C-7), 126.5 (d, C-17), 128.2, 128.4, 128.8, 128.9, 129.0 (5 × 2 d, C-2, C-3, C-10, C-11, C-16), 128.7 (d, C-12), 129.7 (2 d, C-15), 133.4 (d, C-4), 135.4, 136.5, 138.5 (3 s, C-1, C-9, C-14), 140.2 (d, C-6), 213.0 (s, C-18). Anal. Calcd for C₂₅H₂₄O₃S₃ (468.66): C, 64.07; H, 5.16. Found: C, 63.91; H, 5.35.
Spectroscopic data of 8: ¹H NMR (300 MHz, CDCl₃): δ = 3.20 (s, 1 H, 8-H), 4.85 (d, J _7a,8 = 1.3 Hz, 1 H, 7-H_a), 4.94 (d, J _7b,8 = 1.0 Hz, 1 H, 7-H_b), 6.96 (dd, J _15,16 = 7.9 Hz, J _15,17 = 1.3 Hz, 2 H, 15-H), 7.16 (tt, J _17,16 = 7.3 Hz, J _17,15 = 2.2 Hz, 1 H, 17-H), 7.22 (dd, J _16,15 = 7.3 Hz, J _16,17 = 7.3 Hz, 2 H, 16-H), 7.33-7.38 (m, 3 H, 10-H, 12-H), 7.51 (dd, J _3,2 = 7.7 Hz, J _3,4 = 7.7 Hz, 2 H, 3-H), 7.58-7.62 (m, 3 H, 4-H, 11-H), 7.82 (s, 1 H, 13-H), 7.90 (dd, J _2,3 = 8.4 Hz, J _2,4 = 1.1 Hz, 2 H, 2-H). ¹³C NMR (125 MHz, CDCl₃): δ = 41.4 (t, C-8), 122.1 (t, C-7), 126.5 (d, C-11), 128.4, 128.7, 128.8, 129.0, 129.8, 130.0 (6 × 2 d, C-2, C-3, C-10, C-11, C-15, C-16), 130.3 (d, C-17), 133.0 (s, C-14), 133.3 (d, C-4), 136.8 (d, C-13), 137.0 (s, C-9), 138.6 (s, C-1), 140.8 (s, C-5), 141.9 (c, C-6).

15 Bernard AM. Frongia A. Piras PP. Secci F. Synlett  2004,  1064 

16

Spectroscopic data of 9: ¹H NMR (300 MHz, CDCl₃): δ = 3.69 (s, 2 H, 9-H), 4.99 (s, 1 H, 8-H_a), 5.31 (s, 1 H, 8-H_b), 6.51 (d, J _5,6 = 16.1 Hz, 1 H, 5-H), 6.88 (d, J _6,5 = 15.2 Hz, 1 H, 6-H), 7.21-7.39 (m, 10 H, 2-H, 3-H, 4-H, 11-H, 12-H, 13-H). ¹³C NMR (125 MHz, CDCl₃): δ = 38.7 (t, C-9), 118,7 (t, C-7), 126.1 (d, C-13), 126.4 (2 d, C-2), 127.5 (d, C-4), 128.4, 128.6, 128.8 (3 × 2 d, C-3, C-11, C-12), 129.1 (d, C-5), 130.6 (d, C-6), 137.2 (s, C-10), 139.4 (s, C-1), 145.0 (s, C-7).