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Volumn 61, Issue 28, 2005, Pages 6726-6742

Chemo- and stereoselectivity in titanium-mediated regioselective ring-opening reaction of epoxides at the more substituted carbon

Author keywords

Allylation; Epoxides; Quaternary carbon; Titanium

Indexed keywords

ALCOHOL DERIVATIVE; ALLYL COMPOUND; CARBON; EPOXIDE; HALIDE; MAGNESIUM SALT; OXIDE; TITANIUM DERIVATIVE;

EID: 20444432673     PISSN: 00404020     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tet.2005.05.006     Document Type: Article
Times cited : (19)

References (85)
  • 8
    • 0002848881 scopus 로고
    • For representative examples for the reaction of epoxides at the activated carbon having two substituents, see: (a) Y. Naruta, and K. Maruyama Chem. Lett. 1987 963 966
    • (1987) Chem. Lett. , pp. 963-966
    • Naruta, Y.1    Maruyama, K.2
  • 11
    • 0034966829 scopus 로고    scopus 로고
    • For a recent study on the regioselective ring-opening reaction of chiral epoxides, see: (d) B.D. Brandes, and E.N. Jacobsen Synlett 2001 1013 1015
    • (2001) Synlett , pp. 1013-1015
    • Brandes, B.D.1    Jacobsen, E.N.2
  • 37
    • 20444465368 scopus 로고
    • Ring-opening reaction of epoxides at the more substituted carbon atom with an equimolar amount of a transition metal complex and iodomethane was also reported, see: T. Hase, A. Miyashita, and H. Nohira Chem. Lett. 1988 219 222
    • (1988) Chem. Lett. , pp. 219-222
    • Hase, T.1    Miyashita, A.2    Nohira, H.3
  • 39
    • 0003780608 scopus 로고
    • Springer Berlin
    • For the epoxide cleavage at the allylic or benzylic position by titanium reagents prepared by chlorotitanium triisopropoxide, see: (a) M.T. Reetz Organotitanium Reagents in Organic Synthesis 1986 Springer Berlin pp 218-219
    • (1986) Organotitanium Reagents in Organic Synthesis
    • Reetz, M.T.1
  • 42
    • 20444441641 scopus 로고    scopus 로고
    • note
    • In some cases, we examined both allylmagnesium chloride and bromide in the ring-opening reaction, and similar results were obtained.
  • 43
    • 20444485439 scopus 로고    scopus 로고
    • note
    • The stereochemistry of 20 is opposite to that of 86 which was obtained by the reaction with allylmagnesium bromide. This stereochemical outcome can be explained by the chelating ability of the titanium reagent to the oxygen atom of the epoxide, which allows the allylation of the ketone from the side of the epoxide oxygen.
  • 44
    • 0001615493 scopus 로고
    • Stereoselective reactions of cyclic epoxides such as substituted cyclohexene oxides with a titanium reagent were already reported, see Ref. 10b. See also, (a) C. Blandy, R. Choukroun, and D. Gervais Tetrahedron Lett. 24 1983 4189 4192
    • (1983) Tetrahedron Lett. , vol.24 , pp. 4189-4192
    • Blandy, C.1    Choukroun, R.2    Gervais, D.3
  • 47
    • 0007312102 scopus 로고
    • For titanium-mediated stereospecific ring-opening reactions of acyclic epoxides, see: (a) K. Sutowardoyo, M. Emziane, and D. Sinou Tetrahedron Lett. 30 1989 4673 4676
    • (1989) Tetrahedron Lett. , vol.30 , pp. 4673-4676
    • Sutowardoyo, K.1    Emziane, M.2    Sinou, D.3
  • 69
    • 20444464958 scopus 로고    scopus 로고
    • note
    • Only a relatively small NOE enhancement was observed between 4-H and the siloxymethyl group.
  • 70
    • 20444456771 scopus 로고    scopus 로고
    • note
    • Halohydrin is one of the representative side products irrespective of the Grignard reagent used, the stereochemistry of which is not determined. No stereo- or regioisomer of the allylated product was detected in the reaction mixture.
  • 71
    • 20444462472 scopus 로고    scopus 로고
    • note
    • Relative stereochemistries of the quaternary carbons were determined by NOE experiment of the corresponding lactones. Typical examples are shown below.
  • 72
    • 20444468978 scopus 로고    scopus 로고
    • note
    • We investigated the titanium-mediated ring-opening reaction of epoxides with benzyl-, crotyl-, or vinylmagnesium halide; however, a complex mixture of unidentified products was obtained in every case.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.