The reaction of methyldiethylsilane with 7,7-dimethyl-3,6-dioxa-1-cyanododecen-11-yn-8 in the presence of platinohydrochloric acid in medium of benzene at equimolar ratio of reagents has been investigated. It has been established that methyldiethylsilane is added to studied enynes exceptionally on triple bond, but in two directions with predominance (67%) of g-product (relatively oxygen atom)