Mizoroki-reaction

Heck vinylation 22 Heck vs. Diels-Alder 278 Heck-Mizoroki reaction 194 Heterocycles, benzocondensed 246, 249, 252... 

Alonso DA, Najera C, Pacheco C (2002) Oxime-derived palladium complexes as very efficient catalysts for the Heck-Mizoroki reaction. Adv Synth Catal 344 172-183... 

This approach sets the stage for an enantiotopos-differentiating olefin metathesis which would allow the enantioselective synthesis of 258. However, the realization of such an approach has not yet been successful [132]. The second building block (259) containing the A ring was synthesized diastereoselectively by a diastereoface-differentiating intramolecular Heck-Mizoroki reaction of the enantiomerically enriched furan 260 [120]. 

Coupling reactions that are included in this chapter are the Heck-Mizoroki reaction, the Suzuki-Miyaiu-a reaction, the Sonogashira reaction, the Kumada-Corriu reaction, the Negishi reaction, allylic substitution and arylation via CH-activation. 

Progress of Hpase-catalyzed ester synthesis in ionic liquid 12CJ01186. Revisiting Heck—Mizoroki reactions in ionic Hquids 13RCA19219. Role of ionic Hquids as supports of catalysts 12H(85)281. 

Scheme 6.48 Unprecedented stereochemical inversion during intramolecular Heck-Mizoroki reaction.

Tietze, L.R, Redert, T., Bell, H.P. et al. (2008) Efficient synthesis of the structural core of tetracyclines by a palladium-catalyzed domino Tsuji-Trost Heck Mizoroki reaction. Chem. Eur. J., 14, 2527-35. 

Hopkins, J.M., Gorobets, E., Wheatley, B.M.M. et al. (2006) Applications of 3,3 disubstituted BINAP derivatives in inter- and intramolecular Heck/Mizoroki reactions. Synlett, 3120. ... 

G.8 THE MECHANISM FOR AN EXAMPLE OF CROSS-COUPLING THE HECK-MIZOROKI REACTION... 

Having seen steps such as oxidative addition, insertion, and reductive elimination in the context of transition metal-catalyzed hydrogenation using Wilkinsons catalyst, we can now see how these same types of mechanistic steps are involved in a mechanism proposed for the Heck-Mizoroki reaction. Aspects of the Heck-Mizoroki mechanism are similar to steps proposed for other cross-coupling reactions as well, although there are variations and certain steps that are specific to each, and not all of the steps below are involved or serve the same purpose in other cross-coupling reactions. 

The Heck-Mizoroki Reaction Using an Aryi Haiide Substrate... 

All of these reactions involve transition metals such as palladium, copper, and ruthenium, usually in complex with certain types of ligands. After we see the practical applications of these reactions for carbon—carbon bond formation, we shall consider some general aspects of transition metal complex structure and representative steps in the mechanisms of transition metal—catalyzed reactions. We shall consider as specific examples the mechanism for a transition metal—catalyzed hydrogenation using a rhodium complex called Wilkinsons catalyst, and the mechanism for the Heck—Mizoroki reaction. 

The Heck-Mizoroki reaction involves palladium-catalyzed coupling of an alkene with an alkenyl or aryl halide, leading to a substituted alkene. The alkene product is generally trans due to a 1,2-elimination step in the mechanism. 

Much of the chemistry of organic transition metal compounds becomes more understandable if we are able to follow the mechanisms of the reactions that occur. These mechanisms, in most cases, amount to nothing more than a sequence of reactions, each of which represents a fundamental reaction type that is characteristic of a transition metal complex. Let us examine three of the fundamental reaction types now. In each instance we shall use steps that occur when an alkene is hydrogenated using a catalyst called Wilkinsons catalyst. In Section G.7 we shall examine the entire hydrogenation mechanism. In Section G.8 we shall see how similar types of steps are involved in the Heck—Mizoroki reaction. 

Other irmovative approaches have been used to promote aromatization, once the RCM reaction involving the two alkenes has been accomplished. These two approaches are shown in Scheme 17.4. In the first one, triene 24 underwent an RCM reaction to afford the exocycUc double bond-containing compound 25 [18]. Use of the rhodium catalyst [RhCl(cod)]j then facihtated formation of the desired phenol 26. Another neat way to accomplish formation of the aromatic benzene ring was to allow the intermediate cyclic Michael acceptor 28 (formed by RCM of 27) to undergo a Heck-Mizoroki reaction with p-methoxybenzenediazonium tetrafluoroborate 30 to afford the second phenol 29 [18]. 

Scheme 1.2 The prototype asymmetric Heck-Mizoroki reaction and its proposed mechanism [12e, f, 13],...

Figure 1.3 Heck-Mizoroki reactions of aryl chlorides catalyzed by Pd/PftBulj [44].

Scheme 1.19 The first NHC-catalyzed Heck-Mizoroki reaction reported by Herrmann s group [51].

Other types of ligands have been used. Of note are the benzotriazole ligands developed by Verma et al. [49]. These ligands have been applied in a variety of cross-coupling reactions, including the Heck-Mizoroki reaction (Figure 1.8). 

Figure 1.7 Heck-Mizoroki reactions using suitabiy functionaiized iLs as reported by Cai and Liu [56],...

Figure 1.8 Heck-Mizoroki reactions using the benzotriazole ligand of Verma et al. [49].

As tdready mentioned above, the intermolecular asymmetric catalytic Heck-Mizoroki reaction was first reported by Hayashi [12d,e, 13,15] and since then various groups have made contributions in this area. Of note was the report in 2009 by Guiry s group [57] who achieved enantioselectivities of up to 96% ee, using novel HetPHOX ligands 7a—f for the benchmark reaction with cydohexenyl, phenyl, and 2-naphthyl triflate with 2,3-dihydrofuran (Scheme 1.21). The problem with this reaction is the extensive reaction time (7 days) at the elevated temperature of 80 °C. The kinetic product 8 (or... 

Scheme 1.21 Asymmetric Heck-Mizoroki reactions using HetPHOX ligands as reported by Fitzpartick et al. [57],...

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