Alkynylation of C - H bonds via reaction with acetylenic triflones

Journal of the American Chemical Society

Volumn 118, Issue 18, 1996, Pages 4486-4487

  Gong, Jianchun ^a   Fuchs, P L ^a  

^a PURDUE UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

1,2 DICHLOROETHANE; ACETYLENE; ALKYNYL GROUP; CYCLOHEPTANE DERIVATIVE; CYCLOHEXANE; CYCLOPENTANE; TETRAHYDROFURAN;

ARTICLE; CHEMICAL STRUCTURE; COMPETITIVE INHIBITION; DRUG ACTIVATION; HYBRIDIZATION; HYDROGEN BOND; NONHUMAN; REACTION ANALYSIS;

EID: 0029948475     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja953518p     Document Type: Article

References (24)

1. Syntheses via Vinyl Sulfones. 61. Triflone Chemistry 5.
2. Acetylenic triflones have traditionally been prepared in 50-70% yield by addition of triflic anhydride to a solution of acetylenic anion (Hanack, M.; Wilhelm, B.; Subramanian, L. R. Synthesis 1988, 88, 592-595); however, we have found thai inverse addition substantially improves the yield (J. Xiang, A. Mahadevan, P. L. Fuchs, submitted for publication).
3. Acetylenic triflones have traditionally been prepared in 50-70% yield by addition of triflic anhydride to a solution of acetylenic anion (Hanack, M.; Wilhelm, B.; Subramanian, L. R. Synthesis 1988, 88, 592-595); however, we have found thai inverse addition substantially improves the yield (J. Xiang, A. Mahadevan, P. L. Fuchs, submitted for publication).
4. Acetylenic triflones have been previously reported to react with alcohols, DMF, and DMSO: (a) Massa, F.; Hanack, M.; Subramanian, L. R. J. Fluorine Chem. 1982, 19, 601. (b) Hanack, M.; Willhelm, B. Angew. Chem., Int. Ed. Engl. 1989, 28, 1057.
5. Acetylenic triflones have been previously reported to react with alcohols, DMF, and DMSO: (a) Massa, F.; Hanack, M.; Subramanian, L. R. J. Fluorine Chem. 1982, 19, 601. (b) Hanack, M.; Willhelm, B. Angew. Chem., Int. Ed. Engl. 1989, 28, 1057.
6. While Freon 112 and perfluorohexane are unreactive with 1a,b, they do not accommodate clean alkynylation reactions.
7. 2CN is also a good reaction solvent. Adamantane gives 81% product with acetylenic triflone 1a (compare Table 1, entry 17).
8. When this reaction was conducted under the photolytic conditions (condition D), a 1:1 mixture of cycloheptylphenylacetylene and compound 22 was produced in 80% yield. Examination of the crude product from the thermal reaction (condition B) reveals only traces of compound 22. Apparently the cycloheptyl radical undergoes partial oxidation to cycloheptene (20), which then produces 22 as shown in Scheme 2. No evidence for similar products was seen in the reactions of cyclopentane or cyclohexane
9. Both products 8 and 9 are one major (>3:1) diastereomer. The stereochemical assignment has yet to be undertaken, but on the basis of mechanistic arguments (axial attack from die most stable radical intermediate), it is expected that 8 bears the trans-dimethyl configuration, while 9 has the trans-methyl/alkynyl geometry.
10. 13C NMR of the product uniquely defines the regiochemistry, while decoupling of the proton spectra is indicative of the exostereochemistry.
11. Eaton, P. E.; Galoppini, E.; Gilardi, R. J. Am. Chem. Soc. 1994, 116, 7588.
12. Stang, P. J. Chem. Rev. 1978, 78, 383.
13. Radical addition to the α-carbon of β-phenylvinyl phenyl sulfone and β-phenylethynyl phenyl sulfone is known: Russell, G. A.; Ngoviwatchai, P. J. Org. Chem. 1989, 54, 1836 and references cited therein.
14. (a) Langlois, B. R.; Laurent, E.; Roidot, N. Tetrahedron Lett. 1992, 33, 1291.
15. (b) Hu, C.-M.; Qing, F.-L.; Huang, W.-Y. J. Org. Chem. 1991, 56, 2801.
16. (c) Huang, W.-Y.; Hu, L.-Q. J. Fluorine Chem. 1989, 44, 25.
17. (d) Langlois, B. R.; Laurent, E.; Roidot, N. Tetrahedron Lett. 1991, 32, 7525.
18. Medebielle, M.; Pinson, J.; Saveant, J.-M. J. Am. Chem. Soc. 1991, 113, 6872.
19. For a set of recent references describing the value of trifluoromethylated organics, see: Umemoto, T.; Adachi, K. J. Org. Chem. 1994, 59, 5692.
20. For references describing the addition of trifluoromethyl radicals to olefins, see: (a) Uneyama, K.; Kitagawa, K. Tetrahedron Lett. 1991, 32, 375.
21. (b) Chen, Q.-Y.; Yane, Z.-Y. J. Chem. Soc., Chem. Commun. 1986, 498.
22. Compound 21 is assigned trans stereochemistry based upon the dt (J = 4, 10.5 Hz) of the propargylic methine; compound 22 is a single diastereomer, of currently unknown stereochemistry (Scheme 2).
23. 3 group.
24. For an excellent review on the oxidation of unactivated C-H bonds, see: Crabtree, R. H.; Habib, A. In Comprehensive Organic Synthesis; Ley, S. V., Vol. Ed.; Trost, B. M., Fleming, I., Series Eds.; Pergamon Press: New York. 1991;Vol. 7, pp 1-20.