Attempted preparation of 1, 4-pentadiyne

• Main Author: Todd, John M.
• Language: en_US
• Published: Boston University 2016
• Online Access: https://hdl.handle.net/2144/18627

Thesis (M.A.)--Boston University === Several members of the series of compounds known as skipped diynes have been synthesized by the coupling of acetylenic Grignard reagents with propargyl bromides in the presence of such cataylets as cuprous chloride. The simplest possible diyne, 1,4-pentadiyne, has never been synthesized. It was hoped that the action of ethynyl Grignard reagent on propargyl bromide in the presence of ouprous chloride would produce 1,4-pentadiyne. Evidence is presented, however, that although Grignard reagent is rapidly consumed even in the absence of catalyst, no reasonable amount of 1,4-pentadiyne is present in the product mixture. A polymerization mechanism is suggested to account for the large amounts of tars produced by the reactions. It was hoped that 1,4-pentadiyne could be synthesized through the action of ethynyl Grignard reagent on either propargyl tesylate or propargyl mesylate. Evidence is presented, however, that only the halide coupling product, propargyl bromide, is present in either reaction mixture in reasonable yield. Ethynyl Grignard reagent was studied carefully, and estimates of its purity in each of two solvents were made. [TRUNCATED]