Petasis synthesis

Nicolaou, K.C. Petasis, N. A. Selenium in Natural Products Synthesis, CIS Philadelphia, 1984. 

Both the Tebbe and Petasis reagents, Cp2CH2ClAlMe2 and Cp2TiMe2, effect the direct conversion of alkenic esters to dihydropyrans. This olefin metathesis has been successfully applied to the synthesis of complex polyether frameworks <96JA1565,96JA10335>. 

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. 

In recent years, many novel MCRs - including Michael addition-initiated three-component domino sequences [10], Knoevenagel/hetero-Diels-Alder-based MCRs [11], radical chain MCRs [12], transition metal-catalyzed Pauson-Khand MCRs [13], as well as Petasis MCRs [14], have been added to the chemisf s armamentarium and successfully applied to all fields of organic synthesis. 

Scheme 21. Titanium-mediated metathesis strategy for the synthesis of cyclic enol ethers and hydroxy olefins, (a) Tebbe reagent (93), THF, reflux, 41% (140), 41% (143) (b) Petasis reagent (110), THF, reflux, 60% (141), 30% (144) (Nicolaou et al.) [34a]...

Nicolaou KC, Petasis NA (1984) Selenium in Natural Product Synthesis, CIS Inc, Philadelphia... 

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

See The Petasis modification of the Tebbe Reagent.1 N. A. Petasis, Encyclopedia of Reagents for Organic Synthesis, John Wiley and Sons, Inc., L. A. Paquette, Ed., New York, 1995 1, 470 [1271-66-5]... 

Similarly, the reaction of alkenyl boronic acids with azomethines can be found. Indeed, the corresponding 3-CR was used by Petasis [33] for the enantioselective synthesis of a-amino acids starting from amines, a-keto acids and alkenyl boronic acids. 

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