Efficient Olefin Isomerization-Ring-Closing Metathesis Reaction in Sterically Hindered Systems: Study on Simultaneous Use of the Grubbs Metathesis and Ruthenium Hydride Isomerization Catalysts

Abstract

Efficient double bond isomerization-ring-closing metathesis reaction is observed when sterically congested 1,9-dienes are treated with Grubbs ruthenium catalysts; simultaneous use of Grubbs catalyst and RuClH(CO)(PPh₃)₃ facilitate isomerization-metathesis reactions.

annulations - fused-ring systems - metathesis - ruthenium hydrides - tandem reactions

References

For selected reviews on metathesis reaction, see:

1a Grubbs RH. Chang S. Tetrahedron  1998,  54:  4413 

1b Fürstner A. Angew. Chem. Int. Ed.  2000,  39:  3013 

1c Deiters A. Martin SF. Chem. Rev.  2004,  104:  2199 

2 For a recent review, see: Schmidt B. Eur. J. Org. Chem.  2004,  1865 

3 Bielawski CW. Louie J. Grubbs RH. J. Am. Chem. Soc.  2000,  122:  12872 

4 Louie J. Bielawski CW. Grubbs RH. J. Am. Chem. Soc.  2001,  123:  11312 

5 Simal F. Demonceau A. Noels AF. Angew. Chem. Int. Ed.  1999,  38:  538 

For selected recent references, see:

6a Schmidt B. J. Org. Chem.  2004,  69:  7672 

6b Van Otterlo WAL. Ngidi EL. de Koning CB. Tetrahedron Lett.  2003,  44:  6483 

6c Sutton AE. Seigal BA. Finnegan DF. Snapper ML. J. Am. Chem. Soc.  2002,  124:  13390 

7a Maynard HD. Grubbs RH. Tetrahedron Lett.  1999,  40:  4137 

7b Fürstner A. Thiel OR. Ackermann L. Schanz HJ. Nolan SP. J. Org. Chem.  2000,  65:  2204 

7c Bourgeois D. Pancrazi A. Ricard L. Prunet J. Angew. Chem. Int. Ed.  2000,  39:  726 

8 For mechanistic studies, see: McGrath DV. Grubbs RH. Organometallics  1994,  13:  224 

9 Michalak K. Michalak M. Wicha J. Tetrahedron Lett.  2005,  46:  1149 

10a Krompiec S. Kuznik N. Bieg T. Adamus B. Majnusz J. Grymel M. Pol. J. Chem.  2000,  74:  1197 

10b Krompiec S. Pigulla M. Bieg T. Szczepankiewicz W. Kuznik N. Krompiec M. Kubicki M. J. Mol. Catal. A: Chem.  2002,  189:  169 

11 For consecutive use of 7 and then 5, see: van Otterlo WAL. Pathak R. de Koning CB. Synlett  2003,  1859 

12 For the use of 5 together with a hydrogenation catalyst, see: Cossy J. Bargiggia FC. BouzBouz S. Tetrahedron Lett.  2002,  43:  6715 

13

Typical Procedures.
Methyl (3a R* ,4 R* ,8a R* )-8a-Methyl-1-oxo-1,2,3,3a,4,5,8,8a-octahydroazulene-4-carboxylate (10)
To a solution of 6 (3.9 mg, 0.0048 mmol, 3% mol) in benzene (10 mL), diene 8 (42 mg, 0.159 mmol) in benzene (10 mL) was added and the mixture was heated under reflux for 72 h. Then solvent was evaporated, and the residue was purified by chromatography on silica gel (5% EtOAc-hexanes) to give 10 (oil, 20 mg, 56%): HPLC. t _R = 6.42 min, 94% purity (RI detector, MeOH-H₂O = 6:4). ¹H NMR (500 MHz): δ = 6.08-5.97 (m, 1 H), 5.82-5.71 (m, 1 H), 3.67 (s, 3 H), 2.90-2.84 (m, 1 H), 2.72-2.63 (m, 1 H), 2.50-2.33 (m, 3 H), 2.25-2.06 (m, 3 H), 2.04-1.97 (m, 1 H), 1.96-1.87 (m, 1 H), 0.76 (s, 3 H). ¹³C NMR (50 MHz): δ = 221.0, 174.2, 131.5, 127.7, 53.5, 51.5, 49.4, 42.9, 35.5, 35.2, 30.4, 24.2, 14.9. HRMS: m/z calcd for C₁₃H₁₈O₃: 222.1256; found: 222.1262.
S -( tert -Butyl) (3a R* ,4 R* ,8a R* )-7,8a-Dimethyl-1-oxo-1,2,3,3a,4,5,8,8a-octahydroazulene-4-carbothioate (16).
A flame-dried flask equipped with a condenser was charged with 5 (8.8 mg, 0.010 mmol, 5 mol%), 7 (9.9 mg, 0.010 mmol, 5 mol%) and benzene (10 mL). The mixture was briefly stirred to dissolve the catalysts and then ester 12 (69.9 mg, 0.208 mmol) in benzene (10 mL) was added. The solution was heated under reflux for 6 h. The solvent was evaporated and the residue was purified by chromatography on silica gel (5% EtOAc-hexanes) to give 16 (61.1 mg, 100%). ¹H NMR (200 MHz): δ = 5.69 (br t, J = 6.0 Hz, 1 H), 2.95-2.85 (m, 1 H), 2.65-1.90 (m, 9 H), 1.78 (s, 3 H), 1.44 (s, 9 H), 0.86 (s, 3 H). ¹³C NMR (50 MHz): δ = 222.8, 201.5, 136.9, 123.4, 53.2, 52.8, 49.0, 48.0, 40.2, 35.4, 30.0, 29.7, 27.4, 24.0, 15.7. HRMS: m/z calcd for C₁₇H₂₆O₂S: 294.1654; found: 294.1651.

14 Confer: Bourgeois D. Pancrazi A. Nolan SP. Prunet J. J. Organomet. Chem.  2002,  643:  247 

15

The respective β,γ-unsaturated thioester was isolated in ca. 5% yield.
Typical Procedure for S -( tert -Butyl) (2 R* )-2-[(1 R* ,2 R* )-2-Methyl-2-(2-methylprop-2-enyl)-3-oxocyclo-pentyl]hex-4-enethioate (20).
To a solution of 7 (5.1 mg, 0.054 mmol, 1% mol) in benzene (4 mL), 12 (180.6 mg, 0.54 mmol) in benzene (4 mL) was added and the mixture was heated under reflux for 10 min (GC analysis indicated consumption of the substrate). The solvent was evaporated and the residue was purified by chromatography on silica gel (5% EtOAc-hexanes) to give 20 (157.1 mg, 87%). R _f = 0.64 (10% EtOAc-hexanes). GC: 15.5 and 15.9 (E:Z = 2.6:1, 150-250 °C, 150 °C, 1 min, 10 °C/min). ¹H NMR (200 MHz): δ = 5.64-5.26 (m, 2 H), 4.85 (br s, 1 H), 4.68 (br s, 1 H), 2.76-1.96 (m, 10 H), 1.63 (d, J = 5.2 Hz, 3 H), 1.58 (s, 3 H), 1.45 (s, 9 H), 1.03, 1.02 (s, 3 H). ¹³C NMR (50 MHz): δ = 222.6, 202.4, 141.5, 127.8, 126.9, 126.2, 126.0, 115.2, 55.1, 54.7, 51.6, 48.5, 43.7, 42.5, 37.5, 34.8, 29.7, 28.9, 24.6, 23.4, 23.3, 20.2, 17.8. HRMS: m/z calcd for C₃₂H₄₈O₆Na: 336.2123; found: 336.2126.

16a Mukaiyama T. Tamura M. Kobayashi S. Chem. Lett.  1987,  743 

16b Narasaka K. Soai K. Mukaiyama T. Chem. Lett.  1974,  1223 

17a Tsuji J. Minami I. Shimizu I. Chem. Lett.  1983,  1325 

17b

Typical Procedure for S -( tert -Butyl) (2 R* )-2-[(1 R* ,2 R* )-2-Allyl-2-methyl-3-oxocyclopentyl]hex-5-enethioate (15). To a solution of 1-(tert-butylthio)-1-trimethylsilyloxyhexa-1,5-diene (1.551 g, 6 mmol, 1.2 equiv) in CH₂Cl₂ (45 mL), TMSOTf (45 µL, 0.3 mmol, 5 mol%), 2-methylcyclopent-2-en-1-one (0.5 mL, 5 mmol) were consecutively added at
-78 °C. The mixture was stirred for 3 h and then the reaction was quenched with 2-pyridinemethanol (36 µL, 0.37 mmol, 7.5 mol%). After 15 min, hexane (90 mL) was added, the bright yellow solution was filtered through silica gel (10 g, deactivated with 2% Et₃N in hexane), and the solvent was evaporated to give tert-butyl (2R*)-2-{(1R*)-2-methyl-3-[1,1,1-(trimethylsilyl)oxy]-2-cyclopentenyl}-5-hexene-thioate (silyl enol ether, oil, 1.806 g, 98%). To a solution of Pd₂ (dba)₃ (137 mg, 0.15 mmol, 3 mol%) and dppe (356 mg, 0.92 mmol, 18 mol%) in THF (24 mL), the crude silyl enol ether in THF (12 mL) and allyl methyl carbonate (1.138 g, 9.8 mmol) were added. The mixture was heated under refluxed for 6 h, cooled and the solvent was evaporated. The residue was purified by chromatography on silica gel (3% EtOAc-hexanes) to give 15 (yellow oil, 1.58 g, 68%):
¹H NMR (200 MHz): δ = 5.90-5.50 (m, 2 H), 5.10-4.92 (m, 4 H), 2.70-2.25 (m, 4 H), 2.20-1.85 (m, 5 H), 1.80-1.55 (m, 3 H), 1.49 (s, 9 H), 1.01 (s, 3 H). ¹³C NMR (50 MHz):
δ = 221.9, 202.9, 137.8, 133.8, 118.7, 115.3, 54.0, 52.3, 48.7, 43.1, 39.8, 37.5, 30.8, 29.6, 23.4, 18.7. HRMS: m/z calcd for C₁₉H₃₀O₂S: 322.1967; found: 322.1970.