esterlike

Esterlike is an informal term used in chemistry to describe functional groups or molecules that resemble esters in structure or reactivity, though not necessarily possessing the canonical ester linkage R-C(=O)-O-R'. It is a descriptive, not a formal IUPAC designation, and its exact meaning can vary by context.

In practice, esterlike motifs include thioesters (R-C(=O)-SR′) and selenoesters (R-C(=O)-SeR′), where a heteroatom other than oxygen replaces the alkoxy oxygen of a typical ester. These groups share a carbonyl adjacent to an acyl-oxygen or analogous leaving group, and they often participate in acyl-transfer reactions and hydrolysis with similarities to esters, albeit with different rates and selectivities due to the leaving-group ability and bond strengths of sulfur or selenium compared with oxygen.

In biochemistry, esterlike behavior is evident in intermediates such as thioesters (for example, acetyl-CoA) that execute acyl transfer processes essential to metabolism. In materials science and polymer chemistry, esterlike linkages may describe structures that mimic ester chemistry in terms of hydrolysis or transesterification, including certain carbonate- or mixed- linkage systems that exhibit ester-like reactivity.

Limitations and cautions: the label esterlike is interpretive and not a precise classification. Distinctions from true esters can be significant in terms of reactivity, stability, and catalytic behavior, so care is needed when applying the term in theoretical discussions or practical design.

See also: ester, thioester, selenoester, lactone, acyl transfer, hydrolysis, transesterification.