The Eschenmoser sulfide contraction is an

organic reaction Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions, mechanistic organ ...

first described by

Albert Eschenmoser Albert Jakob Eschenmoser (5 August 1925 – 14 July 2023) was a Swiss organic chemist, best known for his work on the synthesis of complex heterocyclic natural compounds, most notably vitamin B12. In addition to his significant contributions to ...

for the synthesis of

1,3-dicarbonyl compound In organic chemistry, a dicarbonyl is a molecule containing two carbonyl () groups. Although this term could refer to any organic compound containing two carbonyl groups, it is used more specifically to describe molecules in which both carbonyls ...

s from a

thioester In organic chemistry, thioesters are organosulfur compounds with the molecular structure . They are analogous to carboxylate esters () with the sulfur in the thioester replacing oxygen in the carboxylate ester, as implied by the thio- prefix ...

. The method requires a base and a tertiary phosphine. The method is of some relevance to

organic chemistry Organic chemistry is a subdiscipline within chemistry involving the science, scientific study of the structure, properties, and reactions of organic compounds and organic matter, organic materials, i.e., matter in its various forms that contain ...

and has been notably applied in the vitamin B₁₂ total synthesis. : Eschenmoser sulfur contraction

A base abstracts the labile hydrogen atom in the thioester, a sulfide anion is formed through an

episulfide In organic chemistry, an episulfide is an organic compound that contain a saturated, heterocyclic ring consisting of two carbon atoms and one sulfur atom. It is the sulfur analogue of an epoxide or aziridine. They are also known as thiiranes, ol ...

intermediate which is removed by the phosphine. : Eschenmoser sulfur contraction mechanism

Scope

The Eschenmoser sulfide contraction method has been employed in a number of

total synthesis Total synthesis, a specialized area within organic chemistry, focuses on constructing complex organic compounds, especially those found in nature, using laboratory methods. It often involves synthesizing natural products from basic, commercially ...

efforts, like that of ''fuligocandin A and B'',

cocaine Cocaine is a tropane alkaloid and central nervous system stimulant, derived primarily from the leaves of two South American coca plants, ''Erythroxylum coca'' and ''Erythroxylum novogranatense, E. novogranatense'', which are cultivated a ...

, ''diplodialide A'' and ''isoretronecanol'' An example of general synthetic utility is the synthesis of novel

carbapenem Carbapenems are a class of very effective antibiotic agents most commonly used for treatment of severe bacterial infections. This class of antibiotics is usually reserved for known or suspected multidrug-resistant (MDR) bacterial infections. Si ...

s ''A new synthetic method of 1β-methylcarbapenems utilizing the eschenmoser sulfide contraction'' Tetrahedron Letters, Volume 35, Issue 14, 4 April 1994, Pages 2187-2190 Osamu Sakurai, Tsuyoshi Ogiku, Masami Takahashi, Hiroshi Horikawa, Tameo Iwasaki : Eschenmoser sulfur contraction sakurai 1994

Eschenmoser sulfur contraction sakurai 1994

References

{{Reflist, 2 Organic reactions Name reactions