2-Zincoethylzincation of 2-Alkynylamines and 1-Alkynylphosphines Catalyzed by Titanium(IV) Isopropoxide and Ethylmagnesium Bromide

Titanium(IV) isopropoxide and ethylmagnesium bromide catalyzed reaction of 2-alkynylamines with Et 2 Zn, followed by deuterolysis/hydrolysis and iodinolysis, affords substituted ( Z )-pent-2-en-2,5- d 2 -1-amines, ( Z )-pent-2-en-1-amines (65–88%), and substituted ( Z )-2,5-diiodopent-2-en-1-amines (55–63%). It is suggested that the reaction proceeds through the formation of cyclic organotitanium derivatives. The reaction between 1-alkynylphosphines and Et 2 Zn in the presence of catalytic amounts of Ti(O- i Pr) 4 and EtMgBr leads to trisubstituted 1-alkenylphosphine oxides with high regioselectivity and stereoselectivity.