The coupling occurs with predictable stereochemistry to give a mixture of two diol products in greater than 60% yield. Retropinacolcrosspinacol coupling reactions a catalytic access. Comprehensive organic synthesis 2nd edition elsevier. Asymmetric pinacol coupling reactions of benzaldehyde with titanium reagents. Carbonyl coupling reactions catalytic in titanium and the use of. Pinacol coupling reaction, 9786916299, please note that the content of this book primarily consists of articles available from wikipedia or other free sources online. An easy route to hexahydroazepine cores from garner aldehydes. Under mild conditions, a novel class of polysubstituted cyclopentane1,2diols have been obtained with excellent diastereoselectivity. Since its introduction to organic synthesis in 1977 by kagan,1,2 samariumii iodide smi2. Dry the organic layer by stirring over dry magnesium sulfate.
Balanol, all stereoisomers, theirntosyl analogues, and fully protected ophiocordin. Herein we describe a catalytic direct pinacol coupling process which proceeds via a. Diastereoselective inter and intramolecular pinacol coupling of. Asymmetric pinacol coupling reactions with a stoichiometric amount of titanium salts have been observed using a combination of ticl 3 and chiral amines such as n,n,n. Potential pinacol coupling substrate 23 could not be made available for investigation due to intervening. The second edition of comprehensive organic synthesis winner of the 2015 prose. On the stereochemistry of the titaniuminduced intramolecular pinacol coupling reaction. New families of reagents for the pinacol coupling reaction. Periplanone total synthesis via intramolecular pinacol.
The reaction is named after pinacol also known as 2,3dimethyl2,3butanediol or tetramethylethylene glycol, which is the product of this. Pinacol coupling modern carbonyl chemistry wiley online library. Crosscoupling reactions using samariumii iodide cyberleninka. A pinacol coupling reaction is an organic reaction in which a carboncarbon covalent bond is formed between the carbonyl groups of an aldehyde or a ketone in presence of an electron donor in a free radical process. A novel account for the synthesis of unsymmetrical 1,2diols based on a. Total synthesis of polycavernosides a and b, two lethal toxins from red alga. Stereospecific total synthesis of gibberellic acid. A convenient synthesis of unsymmetrical pinacols by coupling of structurally similar aromatic aldehydes mediated by lowvalent titanium x. A pinacol coupling reaction is an organic reaction in which a carboncarbon covalent bond is formed between the carbonyl groups of an aldehyde or a ketone in.
A pinacol coupling reaction is an organic reaction in which a carbon carbon covalent bond is formed between the carbonyl groups of an aldehyde or a ketone in presence of an electron donor in a free radical process ref1. Znincl 3mediated pinacol crosscoupling reactions of aldehydes with. Applications of the pinacol coupling reaction i n the total synthesis of natural products. Download citation pinacol coupling introductionbackground applications of the pinacol coupling reaction i n the total synthesis of natural productsnew families of reagents for the. Periplanone total synthesis via intramolecular pinacol coupling.
A green and practical intramolecular pinacol coupling reaction promoted by incl3al catalysts in aqueous media has been developed. Pinacol coupling reaction organic chemistry portal. Molecules free fulltext diastereoselective synthesis. A pinacol coupling reaction is an organic reaction in which a. Znincl3mediated pinacol crosscoupling reactions of aldehydes with. Please note that the content of this book primarily consists of articles available. New catalytic protocols for the pinacol coupling reaction. Strategic use of pinacolterminated prins cyclizations in targetoriented total synthesis larry e. Khand cyclization as a novel and general stereoselective. We have carried out an enantioselective synthesis of periplanone c by a route involving titaniuminduced, intramolecular pinacol coupling reaction of a 1,10 keto aldehyde as the key step. An improvement in the reaction involves trapping the initial coupling product as the bis trimethylsilyl derivative. A short 5 step, efficient synthesis of sarcophytol b 1 from farnesal is reported using a lowtemperature, titaniuminduced pinacol coupling reaction of 1,14dialdehyde5 as the key step. Bring elaboration, pinacol coupling, and end game to 2.
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