**1. Introduction**

Recently we found that the reaction of 1-alkynylphosphines and substituted propargylamines with Et2Zn in the presence of catalytic amounts of reagents, such as titanium(IV) isopropoxide and ethylmagnesium bromide, gives products of triple bond 2-zincoethylzincation [1]. Our study supplements Negishi's work on Ti-Mg-catalyzed cyclozincation of <sup>α</sup>,<sup>ω</sup>-enynes with Et2Zn well [2]. It is known that Cu-, Ni-, Co-, and Ru-catalyzed carbozincation of alkynyl sulfoximines, alkynyl sulfones [3], 1-alkynyl sulfoxides [4], propargylic ethers [5], propargyl alcohols [6], and ynamides [7,8] is an e ffective tool for the synthesis of polysubstituted functionalized olefins. As regards the carbozincation of inactivated alkynes, a limited number of examples are reported in the literature. Ni-catalyzed stereoselective carbozincation of but-1-yn-1-ylbenzene with Ph2Zn is known [9], as well as Co-catalyzed allylzincation of aryl alkynes [10]. As to the e ffective carbozincation of dialkyl substituted alkynes, only ethylzincation [6] and allylzincation [11] of dec-5-yne in the presence of stoichiometric amounts of Cp2ZrI2 were described in the literature. It should be emphasized that the use of a catalytic system consisting of EtMgBr and Ti(O-*i*Pr)4 for 2-zincethylzincation of <sup>α</sup>,<sup>ω</sup>-enynes was first reported by Negishi [2]. Before our study, no examples of carbozincation of alkynylphosphines were known. As regards carbozincation of *N*-containing alkynes, only one example of diastereoselective carbozincation of lithiated ( *R*)-(1)- *N*-methyl-*<sup>N</sup>*-propargyl-1-phenylethylamine with crotylzinc bromide was reported [12]. Therefore, further investigation of the scope of applicability of Ti-Mg-catalyzed carbozincation of functionally substituted acetylene derivatives was of considerable interest. In view of the high demand for ligands based on phosphines as well as their derivatives in organometallic and coordination chemistry [13,14], we studied, first of all, the catalytic carbozincation of 1-alkynylphosphine oxides and -phosphine sulfides.
