Alk-1-yn-1-ols, $\ce{RC≡COH}$; tautomeric with
ketenes $\ce{RCH=C=O}$.
Source: PAC, 1995,
67, 1307. (
Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1375 [
Terms] [
Paper]