Alkyne-based, highly stereo- and regioselective synthesis of stereodefined functionalized vinyl tellurides.

ABSTRACT

(Z)-beta-Aryltellurovinylphosphonates and (Z)-beta-aryltellurovinyl sulfones were synthesized via the highly stereoselective anti-hydrotelluration of 1-alkynylphosphonates and 1-alkynyl sulfones. The configurations of these compounds were characterized via 1H NMR spectra or NOESY experiments and by X-ray diffraction analysis; (E)-beta-aryltellurovinyl sulfones were obtained with the reaction of sodium aryltellurate with (E)-2-iodovinyl sulfones to confirm the stereochemistry of the above anti-hydrotelluration. When the tandem reaction of alkynes with diaryl ditellurides and sodium arylsulfinates was carried out in AcOH/H2O (4/1), the corresponding (E)-beta-aryltellurovinyl sulfones were obtained in one step in good yields. This reaction is highly regio- and stereoselective and proceeds by using arylsulfinate as the sulfonyl radical precursor and diaryl ditellurides as free radical acceptors. (E)-1-Iodo-2-aryltelluroalkenes can be obtained by the anti-addition of ArTeI with terminal alkynes in THF. The stereochemistry of compound 17b was also determined by X-ray diffraction analysis.