Synthesis of 1-methyl-4-alkyl-1,3-diacetylenes. Prototropic rearrangement in 1-alkyl-1,3-diacetylenes

Treatment of 2-methyl-2-hydroxy-6-alkyl-3,5-diacetylenes with powdered NaOH was used for the synthesis of terminal 1-alkyl-1,3-butadiynes that can be isolated (54-97%) or used in situ. In an attempt to increase the yields of some of the obtained products, different experimental conditions were studi ed and we found that by using CTAB as a catalyst, a prototropic rearrangeme nt was promoted to afford the 1-methyl-4-alkyl-1,3-diacetylenes in the 62-9 4% yield range. (C) 2001 Published by Elsevier Science Ltd.