Intramolecular homolytic substitution at tellurium: Preparation of a dihydrotellurophene by alkyltelluride-mediated SRN1/SHi reactions
作者:Melissa J. Laws、Carl H. Schiesser
DOI:10.1016/s0040-4039(97)10239-8
日期:1997.12
Reaction of 1-methyl-1-(2-iodophenyl)oxirane (4) with two equivalents of sodium butyltelluroate (NaTeBu), generated throught the sodium borohydride reduction of dibutylditelluride, in THF, affords 2,3-dihydro-3-hydroxy-3-methylbenzo[b]tellurophene (6) in 57% yield, together with 1-(butyltelluro)-2-phenyl-2-propanol (7, 7%). This transformation presumably involves a tandem S(RN)1/S(H)i sequence which was investigated further through the reactions of 1-(benzylseleno)-2-phenyl-2-propanol (2, R-1 = Me; R-2 = H) and 1-allyloxy-2-iodobenzene (9) with sodium butyltelluroate under similar conditions. Mechanistic and kinetic implications are discussed. (C) 1997 Elsevier Science Ltd.
Toward Novel Antioxidants: Preparation of Dihydrotellurophenes and Selenophenes by Alkyltelluride-Mediated Tandem S<sub>RN</sub>1/S<sub>H</sub>i Reactions<sup>1</sup>
作者:Lars Engman、Melissa J. Laws、Jonas Malmström、Carl H. Schiesser、Lisa M. Zugaro
DOI:10.1021/jo9907235
日期:1999.9.1
distributions similar to those observed for reactions involving n-BuTeNa. Lithium or sodium phenyltellurolate returned only starting materials from these reaction mixtures. The 2-[2-(n-butyltelluro)-1-hydroxy-1-methyl]ethylphenyl radical (14) is estimated to cyclize with k(c) = 5 x 10(8) s(-)(1) at 25 degrees C. The tandem S(RN)1/S(H)i sequence has been applied to the preparation of the antioxidant analogues, 5-hydroxy-2