Pham, Manh V. et al. published their research in Angewandte Chemie, International Edition in 2012 | CAS: 16356-02-8

1,4-Dimethoxy-2-butyne (cas: 16356-02-8) belongs to ethers. Ether is less polar than esters, alcohols or amines because of the oxygen atom that is unable to participate in hydrogen bonding due to the presence of bulky alkyl groups on both sides of the oxygen atom. Ethers can form hydrogen bonds with other molecules (alcohols, amines, etc.) that have O―H or N―H bonds. The ability to form hydrogen bonds with other compounds makes ethers particularly good solvents for a wide variety of organic compounds and a surprisingly large number of inorganic compounds.Application of 16356-02-8

Access to sultams by rhodium(III)-catalyzed directed C-H activation was written by Pham, Manh V.;Ye, Baihua;Cramer, Nicolai. And the article was included in Angewandte Chemie, International Edition in 2012.Application of 16356-02-8 This article mentions the following:

Acylated sulfonamides were established as suitable directing groups for rhodium(III)-catalyzed C-H bond activations. The cyclo-metalated intermediates readily react with a broad range of internal alkynes and open a rapid and general access to aryl sultams. In the experiment, the researchers used many compounds, for example, 1,4-Dimethoxy-2-butyne (cas: 16356-02-8Application of 16356-02-8).

1,4-Dimethoxy-2-butyne (cas: 16356-02-8) belongs to ethers. Ether is less polar than esters, alcohols or amines because of the oxygen atom that is unable to participate in hydrogen bonding due to the presence of bulky alkyl groups on both sides of the oxygen atom. Ethers can form hydrogen bonds with other molecules (alcohols, amines, etc.) that have O―H or N―H bonds. The ability to form hydrogen bonds with other compounds makes ethers particularly good solvents for a wide variety of organic compounds and a surprisingly large number of inorganic compounds.Application of 16356-02-8

Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem