Pseudo-Geminally-Substituted [2.2]Paracyclophanes as Spacers for Bisallenyl Sulfoxides and Sulfones

Abstract

The first pseudo-geminally-substituted bisallenic [2.2]paracyclophane system has been synthesized by the [2,3]sigmatropic rearrangement of propargylic sulfenates to the corresponding allenyl sulfoxides.

[2.2]paracyclophanes - sigmatropic rearrangements - ­allenes - sulfenates - sulfones

References

1 For a review see: Hopf H. Angew. Chem. Int. Ed.  2003,  42:  2822 ; Angew. Chem. 2003, 115, 2928

2 Hopf H. In The Chemistry of the Allenes   Landor SR. Academic Press; New York: 1982.  p.563 

For representative references, see:

3a Rossi R. Diversi P. Synthesis  1973,  25 

3b Murray M. In Houben-Weyl, Methoden der Organischen Chemie   Vol. 5/2a:  Müller E. Thieme Verlag; Stuttgart: 1977.  p.963 

3c Hopf H. In The Chemistry of Functional Groups, the Chemistry of Ketenes, Allenes, and Related Compounds   Part 2:  Patai S. J. Wiley and Sons; New York: 1980.  p.779 

3d The Chemistry of the Allenes   Vol I-III:  Landor SR. Academic Press; New York: 1982. 

3e Schuster HF. Coppola GM. Allenes in Organic Synthesis   J. Wiley and Sons; New York: 1980. 

3f Pasto DJ. Tetrahedron  1984,  40:  2805 

3g Modern Allene Chemistry   Krause N. Hashmi ASK. Wiley-VCH; Weinheim: 2004. 

4a Braverman S. In The Chemistry of Sulfenic Acids and their Derivatives   Patai S. Wiley; New York: 1990.  p.311 

4b Braverman S. In The Chemistry of Double-Bonded Functional Groups   Suppl. A2:  Patai S. Wiley; Chichester: 1989.  p.963 

5 Hopf H. Raulfs F.-W. Schomburg D. Tetrahedron  1986,  42:  1655 

6

General Procedure for Compound 2a.
To a solution of 1-pentyne (0.2 mL, 2 mmol) in dry THF (10 mL) a solution of n-BuLi (1.6 M in hexane, 1.25 mL, 2 mmol) was slowly added at -35 °C to -40 °C. The mixture was stirred for 20 min and then a solution of 1 (1 mmol) in dry THF (10 mL) was added dropwise by syringe. After 2 h the reaction mixture was allowed to warm to r.t. and then quenched with a solution of NH₄Cl. The aqueous layer was extracted with CH₂Cl₂ (3 × 30 mL) and combined extracts were washed with H₂O and brine, dried (MgSO₄) and concentrated under vacuum. Crystallization from Et₂O-pentane gave the pure products as colorless crystals. Mp 129-130 °C; yield: 0.35g (89%). IR (neat): 3261, 3049, 2959, 2869, 2222, 1594, 1459, 1419, 1318, 1130, 953 cm^-1. ¹H NMR (400 MHz): δ = 0.85 (6 H, t, ³ J = 7.3 Hz, 2 CH₃), 1.41 (4 H, sextet, ³ J = 7.2 Hz, 2 CH₂), 2.04 (4 H, dt, ³ J = 7.1, ⁵ J = 2 Hz, 2 CH₂), 2.95-3.12 (6 H, m, 3 CH₂), 3.43-3.50 (2 H, m, CH₂), 3.77 (2 H, br s, 2 OH), 5.67 (2 H, t, ⁵ J = 2 Hz, 2 CH), 6.48 (2 H, d, ³ J = 7.7 Hz, 2 CH_ar), 6.53 (2 H, dd, ³ J = 7.7, ⁴ J = 1.8 Hz, 2 CH_ar), 6.77 (2 H, d, ⁴ J = 1.8 Hz, 2 CH_ar). ¹³C NMR (100 MHz): δ = 13.7, 21.1, 22.2, 31.7, 35.4, 61.9, 80.5, 86.8, 127.7, 133.2, 135.0, 135.3, 139.8, 140.4. MS: m/z (%) = 382 (30) [M - H₂O]⁺, 183 (100). Anal. Calcd for C₂₈H₃₂O₂: C, 83.96; H, 8.05. Found: C, 83.82; H, 8.14.

7

Crystal structure determination of 2c. Crystal data: triclinic, space group P-1, a = 9.503 (2), b = 11.749 (2), c = 12.986 (2) Å, α = 112.512 (6)°, β = 98.522 (6)°, γ = 102.400(6)°, Z = 2, T = -100 °C. Data collection: a crystal ca. 0.35 × 0.35 × 0.2 mm was used to record 12829 intensities on a Bruker SMART 1000 CCD diffractometer (Mo K_α radiation, 2θ_max 56.5°). Structure refinement: The structure was refined anisotropically on F ² (program SHELXL-97, G.M. Sheldrick, Univ. of Göttingen) to wR2 = 0.134, R1 = 0.046 for 331 parameters and 6208 unique reflections. Hydroxyl hydrogens were refined freely, others using a riding model. Data have been deposited in Cambridge under the number CCDC 257122.

8

General Procedure for Compound 3a.
To a solution of 2a (0.2 g, 0.5 mmol) and Et₃N (0.14 mL, 1 mmol) in CH₂Cl₂ (8 mL), PCMM (0.11 mL, 1 mmol) was added dropwise at -78 °C. The reaction mixture was stirred for 2 h and then allowed to warm to 0 °C, washed with H₂O, dried (MgSO₄) and concentrated under vacuum. Crystallization from Et₂O-pentane gave the pure products as colorless crystals. Mp 134-135 °C; yield: 0.29g (84%). IR (neat): 2962, 2929, 1928, 1588, 1456, 1095, 806, 779 cm^-1. ¹H NMR (400 MHz): δ = 0.99-1.03 (4 × 6 H, t, 4 × 2 CH₃), 1.55-1.68 (4 × 4 H, m, 4 × 2 CH₂), 2.42-2.65 (4 × 4 H, m, 4 × 2 CH₂), 2.93-3.06 (4 × 6 H, m, 4 × 3 CH₂), 3.54-3.60 (4 × 2 H, m, 4 × CH₂), 6.42-6.56 (4 × 6 H, m, 4 × 6 CH_ar), 6.84 (0.4 H, t, ⁵ J = 3.2 Hz, 2 CH_allene), 6.99 (1.2 H, t, ⁵ J = 3.0 Hz, 2 CH_allene), 7.18 (1.2 H, t, ⁵ J = 3.2 Hz, 2 CH_allene), 7.26 (5.2 H, t, ⁵ J = 3.1 Hz, 2 CH_allene). ¹³C NMR (100 MHz, spectroscopic data for the major diastereoisomer): δ = 13.9, 22.6, 27.8, 32.4, 34.8 103.9, 108.4, 113.3, 131.0, 133.2, 133.5, 135.2, 137.8, 140.0, 208.4. MS: m/z (%) = 696 (0.5) [C₃₀H₃₀ ³⁵Cl₆O₂S₂]⁺, 413 (100). Anal. Calcd for C₃₀H₃₀Cl₆O₂S₂: C, 51.52; H, 4.32; Cl, 30.41; S, 9.17. Found: C, 51.81; H, 4.47; Cl, 30.15; S, 8.82.

9 Hopf H. In Strain and its Implications in Organic Chemistry   Vol. 273:  Meijere A. Blechert S. NATO ASI Series, Series C, Kluver Academic Publisher; London: 1989.  p.297 

10 Adam W. Bialas J. Hadjiarapoglu L. Chem. Ber.  1991,  124:  2377 

11

General Procedure for Compound 4a.
To a solution of 3a (0.175 g, 0.25 mmol) in acetone (10 mL) a solution of DMDO (0.05 M in acetone, 10 mL, 0.5 mmol) was added. The reaction mixture was stirred at r.t. until the starting material had been consumed (ca. 2 h, TLC mon-itoring on silica gel with CH₂Cl₂) and then concentrated under vacuum. The crude product was diluted with CH₂Cl₂ and filtered through a thin layer of silica gel. Crystallization from Et₂O gave the pure products as colorless crystals. Mp 156-157 °C dec.; yield: 0.07 g (40%). IR (neat): 2962, 2931, 1931, 1592, 1457, 1347, 1153, 1100, 799 cm^-1. ¹H NMR (200 MHz): δ = 1.01 (6 H, t, ³ J = 7.2 Hz, 2 CH₃), 1.64 (4 H, sextet, ³ J = 7.5 Hz, 2 CH₂), 2.68 (4 H, m, 2 CH₂), 2.97-3.04 (6 H, m, 3 CH₂), 3.46-3.55 (2 H, m, CH₂), 6.54 (6 H, s, 6 CH_ar), 7.18 (2 H, t, ⁵ J = 3.1 Hz, 2 CH_allene). ¹³C NMR (50 MHz): δ = 13.6, 22.3, 32.3, 32.8, 34.7 102.7, 104.7, 107.9, 129.4, 133.6, 134.0, 135.4, 137.8, 140.4, 214.6. MS:
m/z (%) = 728 (0.3) [C₃₀H₃₀ ³⁵Cl₆O₄S₂]⁺, 183 (100). Anal. Calcd for C₃₀H₃₀Cl₆O₄S₂: C, 49.26; H, 4.13; Cl, 29.08; S, 8.77. Found: C, 49.03; H, 4.05; Cl, 28.86; S, 8.52.

12 Sankararaman S. Hopf H. Dix I. Jones PG. Eur. J. Org. Chem.  2000,  2703