Achmatowicz reaction

{{Short description|Organic synthesis}}{{Reactionbox

| Name = Achmatowicz reaction

| Type = Rearrangement reaction

| NamedAfter = Osman Achmatowicz Jr.

| Section3 = {{Reactionbox Identifiers

| RSC_ontology_id = 0000233

}}

}}

The Achmatowicz reaction, also known as the Achmatowicz rearrangement, is an organic synthesis in which a furan is converted to a dihydropyran. In the original publication by the Polish chemist Osman Achmatowicz Jr. (b. 20 December 1931 in Vilnius) in 1971 {{Cite journal|last1=Achmatowicz|first1=O.|last2=Bukowski|first2=P.|last3=Szechner|first3=B.|last4=Zwierzchowska|first4=Z.|last5=Zamojski|first5=A.|date=1971-01-01|title=Synthesis of methyl 2,3-dideoxy-DL-alk-2-enopyranosides from furan compounds: A general approach to the total synthesis of monosaccharides|journal=Tetrahedron|volume=27|issue=10|pages=1973–1996|doi=10.1016/S0040-4020(01)98229-8|issn=0040-4020}} furfuryl alcohol is reacted with bromine in methanol to 2,5-dimethoxy-2,5-dihydrofuran which rearranges to the dihydropyran with dilute sulfuric acid. Additional reaction steps, alcohol protection with methyl orthoformate and boron trifluoride) and then ketone reduction with sodium borohydride produce an intermediate from which many monosaccharides can be synthesised.

:Image:The Achmatowicz reaction.svg

The Achmatowicz protocol has been used in total synthesis, including those of desoxoprosophylline,{{Cite journal|last1=Yang|first1=Cui-Fen|last2=Xu|first2=Yi-Ming|last3=Liao|first3=Li-Xin|last4=Zhou|first4=Wei-Shan|date=1998-12-10|title=Asymmetric total synthesis of (+)-desoxoprosophylline|journal=Tetrahedron Letters|volume=39|issue=50|pages=9227–9228|doi=10.1016/S0040-4039(98)02129-7|issn=0040-4039}} pyrenophorin {{Cite journal|last1=Kobayashi|first1=Yuichi|last2=Nakano|first2=Miwa|last3=Kumar|first3=G. Biju|last4=Kishihara|first4=Kiyonobu|date=1998-10-01|title=Efficient Conditions for Conversion of 2-Substituted Furans into 4-Oxygenated 2-Enoic Acids and Its Application to Synthesis of (+)-Aspicilin, (+)-Patulolide A, and (−)-Pyrenophorin|journal=The Journal of Organic Chemistry|volume=63|issue=21|pages=7505–7515|doi=10.1021/jo980942a|pmid=11672404|issn=0022-3263}}{{Cite journal|last1=Zhang|first1=Yongqiang|last2=Liebeskind|first2=Lanny S.|date=2006-01-01|title=Organometallic Enantiomeric Scaffolding: Organometallic Chirons. Total Synthesis of (−)-Bao Gong Teng A by a Molybdenum-Mediated [5+2] Cycloaddition|journal=Journal of the American Chemical Society|volume=128|issue=2|pages=465–472|doi=10.1021/ja055623x|pmid=16402833|issn=0002-7863}} Recently it has been used in diversity oriented synthesisReagents: NBS, PPTS, for macrobeads see: solid-phase synthesis{{Cite journal|last1=Burke|first1=Martin D.|last2=Berger|first2=Eric M.|last3=Schreiber|first3=Stuart L.|date=2004-11-01|title=A Synthesis Strategy Yielding Skeletally Diverse Small Molecules Combinatorially|journal=Journal of the American Chemical Society|volume=126|issue=43|pages=14095–14104|doi=10.1021/ja0457415|pmid=15506774|issn=0002-7863}}

:Image:AchmatowiczBurke2006.svg

and in enantiomeric scaffolding.{{Cite journal|last1=Coombs|first1=Thomas C.|last2=Lee|last3=Wong|first3=Heilam|last4=Armstrong|first4=Matthew|last5=Cheng|first5=Bo|last6=Chen|first6=Wenyong|last7=Moretto|first7=Alessandro F.|last8=Liebeskind|first8=Lanny S.|date=2008-02-01|title=Practical, Scalable, High-Throughput Approaches to η3-Pyranyl and η3-Pyridinyl Organometallic Enantiomeric Scaffolds Using the Achmatowicz Reaction|journal=The Journal of Organic Chemistry|volume=73|issue=3|pages=882–888|doi=10.1021/jo702006z|issn=0022-3263|pmc=2652699|pmid=18171075}}Reagents: benzyl chloroformate protects amine as Cbz group, Achmatowitz reaction with m-CPBA, complexation with a molybdenum compound, Cp is cyclopentadienyl anion

:Image:AchmatowiczReactionCoombs2008.svg