The structures of the alkylated products were established by ir and nmr spectroscopy (see Experimental Section), by the analysis of crystalline carbonyl derivatives (see Table II), and by a variety of chemical reactions characteristic of ketones and terminal ethynyl groups. Furthermore, the dialkylpropargyl moiety was firmly eslablished to be in the position a to the carbonyl by several ring closure reactions (see below). The reactions of the 2-t-alkylated ...
