Petasis reaction reaction

Kumagai, N., Muncipinto, G., Schreiber, S.L. (2006) Short Synthesis of SkeletaHy and Stereo-chemicaUy Diverse Small Molecules by Coupling Petasis Condensation Reactions to Cyclization Reactions. Angewandte Chemie Jnternational Edition, 45, 3635-3638. 

Scheme 6.82 Proposed reactive complex of the Petasis reaction utilizing a-hydroxy aldehydes, amines, and organic boronic acids (A) and bifunctional mode of action of chelating thiourea catalyst 65 in the enantioselective Petasis-type 2-vinylation of N-acetylated quinolinium ions (B).

A straightforward enantioselective synthesis of aZ/o-difluorothreonine is based on a three component Petasis reaction (enantiopure difluorolactic aldehyde. 

This process is now been referred to as the Petasis reaction by several... 

The Petasis Reaction is a multicomponent reaction (MCR) that enables the preparation of amines and their derivatives such as 01-amino acids. 

As in the classical reaction that it resembles, the Petasis Reaction also involves a large number of interdependent equilibrium steps, some of them identical to those in me Mannich Reaction. 

A second, very elegant, example of build/couple/pair strategy in DOS is performed by Schreiber and co-workers (Scheme 5) [51]. This example uses the Petasis reaction of (5)-lactol 42, L-phenylalanine methyl ester (43), and ( )-2-cyclopropylvinylboronic acid (44) as coupling reaction, which is followed by a... 

Sugiyama, S., Aral, S., Ishii, K. Short synthesis of both enantiomers of cytoxazone using the Petasis reaction. Tetrahedron Asymmetry 2004, 15, 3149-3153. 

Golebiowski, A., Klopfenstein, S. R., Chen, J. J., Shao, X. Solid supported high-throughput organic synthesis of peptide 3-turn mimetics via tandem Petasis reaction/diketopiperazine formation. Tetrahedron Lett. 2000,41,4841-4844. 

Wang, Q., Finn, M. G. 2H-Chromenes from Salicylaldehydes by a Catalytic Petasis Reaction. Org. Lett. 2000, 2,4063-4065. 

Hart, S. L., McCamley, A., Taylor, P. C. Ti(Ti5-C5H5)(Ti5-C5H4fBu)(CH2Ph)2. A probe of the course of the Petasis benzylidenation reaction. Syn/eff1999, 90-92. 

Meurer, E. C., Santos, L. S., Pilli, R. A., Eberlin, M. N. Probing the Mechanism of the Petasis Olefination Reaction by Atmospheric Pressure Chemical Ionization Mass and Tandem Mass Spectrometry. Org. Lett. 2003, 5, 1391-1394. 

Problem 6.26. Draw a reasonable mechanism for the following Petasis reaction. 

The Petasis reaction is a mild multicomponent reaction that allows the conden sation of a boronic acid, an amine, and a carbonyl derivative to generate an allylic amine. Although several diastereoselective Petasis reactions have been reported [106], the first catalytic asymmetric reaction was described in 2008 (Scheme 1.29) [107]. It was shown that the condensation proceeds in high yields and enantiomeric excesses, affording the corresponding protected a vinylglycine derivatives. 

In addition to the very important palladium-catalysed reactions, boronic acids undergo a number of useful reactions that do not require transition-metal catalysis, particularly those involving electrophilic ipso-substitutions by carbon electrophiles. The Petasis reaction involves ip,y(9-replacement of boron under Mannich-like conditions and is successful with electron-rich heterocyclic boronic acids. A variety of quinolines and isoquinolines, activated by ethyl pyrocarbonate, have been used as the Mannich reagent . A Petasis reaction on indole 3-boronic acids under standard conditions was an efficient route to very high de a-indolylglycines. " ... 

Another device for bringing thiophenes into reaction with Mannich intermediates is to utilise thiophene boronic acids - the Petasis reaction primary aromatic amines can also be used as the amine component. ... 

The dihydroxybiaryl 97 can be used to exchange with alkenylboronate esters, bringing chirality in close proximity to the reaction site when the boronates participate in a Petasis reaction to build ally lie amines/ ... 

Petasis reaction on quinoline following an analogous course to the Reissert reaction is catalyzed by the thiourea 196, water and NaHCOs are facilitating additives. ... 

In its most general form, the boronic acid Mannich or Petasis reaction18 involves the reaction of boronic acid 22, a carbonyl compound 8, and an amine 23 to produce secondary amines 24. If one uses a-keto acid 25 for the carbonyl component then the corresponding product from the Petasis reaction was a-amino acid 26. The key mechanistic step was proposed to occur intramolecularly with alkyl migration from intermediate boronate ester 28 formed from aminol 27. 

Alcohol-substituted thioureas also catalyse the Petasis-type reaction of quinolines [39] and conjugate addition of amine [40]. 

Yamaoka, Y, Miyabe, H. and Takemoto, Y. (2007) Catalytic enantioselective Petasis-type reaction of quinolines catalyzed by a newly designed thiourea catalyst. Journal of the American Chemical Society, 129, 6686-6687. 

An interesting example of the Petasis reaction was employed as a highly stereoselective synthesis of indolyl jV-substituted glycines by the reaction of indolyl-3-boronic acids <01TL2545>. Thus, reaction of 7V-tosyl-3-indolylboronic acids 176 with (R)-a-methyl-benzylamine (177) and glyoxylic acid (178) provides the indolyl iV-substituted glycines 179 in optically pure form. 

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