Unsymmetrical 1.4-diorganyl-1, 3-butadiyncs la-g undergo rcgio-, stereo-and chemoselective addition of butyltcllurolatc anion leading to (Z)-1-butyltelluro-1, 4-bis (organyl) but-1-en-3-ynes 2a-g in good yields. The terminal triple bond reacts faster than the propargylic triple bond (alcohol derivatives), which is more reactive than the triple bond bearing an alkyl or aryl group. Combination with removal of butyl tellurium moiety from the ...