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The Eschenmoser sulfide contraction is an organic reaction first described by Albert Eschenmoser for the synthesis of 1,3-dicarbonyl compounds from a thioester.〔''Organic syntheses based on name reactions'', Volume 22 2002 Alfred Hassner,C. Stumer〕〔''A New Type of Corrin Synthesis'' Angewandte Chemie International Edition in English Volume 8, Issue 5, Date: May 1969, Pages: 343-348 Yasuji Yamada, D. Miljkovic, P. Wehrli, B. Golding, P. Löliger, R. Keese, K. Müller, A. Eschenmoser 〕〔''Sulfidkontraktion via alkylative Kupplung: Eine methode zur darstellung von -dicarbonylderivaten. Über synthetische methoden'', 1. Mitteilung Helvetica Chimica Acta Volume 54, Issue 2, Date: 1971, Pages: 710-734 M. Roth, P. Dubs, E. Götschi, A. Eschenmoser 〕 The method requires a base and a tertiary phosphine. The method is of some relevance to organic chemistry and has been notably applied in the vitamin B12 total synthesis. :Eschenmoser sulfur contraction.svg A base abstracts the labile hydrogen atom in the thioester, a sulfide anion is formed through an episulfide intermediate which is removed by the phosphine.〔Organic Syntheses, Coll. Vol. 6, p.776 (1988); Vol. 55, p.127 (1976). (Link )〕 :Eschenmoser sulfur contraction mechanism ==Scope== The Eschenmoser sulfide contraction method has been employed in a number of total synthesis efforts, like that of ''fuligocandin A and B'',〔''One-Pot Eschenmoser Episulfide Contractions in DMSO: Applications to the Synthesis of Fuligocandins A and B and a Number of Vinylogous Amides'' Birgitta Pettersson, Vedran Hasimbegovic, Jan Bergman The Journal of Organic Chemistry 2011 76 (6), 1554-1561 〕 cocaine,〔'' Enantiospecific Synthesis of Natural (−)-Cocaine and Unnatural (+)-Cocaine from d- and l-Glutamic Acid'' Ronghui Lin,, Josep Castells, and, Henry Rapoport The Journal of Organic Chemistry 1998 63 (12), 4069-4078 〕''diplodialide A'' 〔''Macrocyclic lactone formation through sulfide contraction. Synthesis of (.+-.)-diplodialide A'' Robert E. Ireland, Frank R. Brown Jr. J. Org. Chem., 1980, 45 (10), pp 1868–1880 〕 and ''isoretronecanol'' 〔''New approaches to the pyrrolizidine ring system: total synthesis of (.+-.)-isoretronecanol and (.+-.)-trachelanthamidine'' Harold W. Pinnick, Yeong-Ho Chang J. Org. Chem., 1978, 43 (24), pp 4662–4663 〕 An example of general synthetic utility is the synthesis of novel carbapenems 〔''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 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Eschenmoser sulfide contraction」の詳細全文を読む スポンサード リンク
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