Cross-metathesis of methyl oleate and cis-2-butene-1,4-diol: a direct route to bifunctional polymer building blocks

The cross metathesis (CM) of methyl oleate (1) and cis-2-butene-1,4-diol (2) was investigated as a direct route to bifunctional polymer building blocks. In most previous cross-metathesis approaches, acrylonitrile has been employed as the CM partner olefin. While internal olefins such as cis-2-butene-1,4-diol have been explored in metathesis reactions, their use without protecting groups has remained challenging. In this study, the unprotected diol enables direct access to highly functionalized intermediates, avoids dimer formation associated with terminal olefins, and allows subsequent isomerization in a single step. Efficient CM was acheived at low temperature (0 °C) using a Stewart-Grubbs catalyst, affording CM product 4 in excellent yield. Compound 4 was readily converted to alcohol 10, aldehyde 13, and olefin 9 in a single step and in >90% yields. These intermediates are useful precursors for specialty chemicals, including 11-aminoundecanoate, the precursor of PA11. A tandem CM/isomerization process from 4 to 13 was also demonstrated for the first time.