Double Heck reaction

A chelation-assisted Pd-catalyzed Cope rearrangement was proposed in the reaction of phenanthroline to generate isoquinolinone derivatives (Eq. 12.78).177 The use of aqueous media and ligands enables a double-Heck reaction on a substrate favoring alkene insertion over (J>-hydride elimination. 

The Shibasaki group [27] developed an enantioselective total synthesis of (+)-xes-toquinone (6/1-38) using an asymmetric double Heck reaction with BINAP as chi-... 

Scheme 6/1.4. Double Heck-reaction for the synthesis of heterocycles.

The same group [38] also developed a double Heck reaction which was then terminated by a Friedel-Crafts alkylation to give 6/1-54 from 6/1-53 (Scheme 6/1.12) this involved an attack of an alkylpalladium(II) intermediate on an aryl or heteroaryl moiety. Noteworthy is the finding that the formal Friedel-Crafts alkylation occurs on both electron-rich and electron-poor heteroaromatic rings, as well as on substituted phenyl rings. Single Heck/Friedel-Crafts alkylation combinations have also been performed. 

To date, only double Heck reactions have been described, but triple Heck reactions are also possible [39]. Reaction of the alkynyl aryl iodide 6/1-55 with norbor-nene in the presence of Pd(OAc)2, triphenylphosphane and triethylamine as base led to the cyclopropanated norbornene derivate 6/1-59 as a single diastereomer in 40% yield (Scheme 6/1.13). It can be assumed that the alkenyl Pd-species 6/1-56 is first formed stereoselectively, and this undergoes a Heck reaction with norbornene... 

Another double Heck reaction was reported by Pan and coworkers [42] to prepare substituted pyrrolines 6/1-67 using the bisallylamine 6/1-67 and benzylchlorides as... 

Scheme 6/1.17. Influence of the substitution pattern on the enantioselectivity in intramolecular double Heck reaction.

New cascade oxidation-dehydrogenation-double-Heck reaction. 

Suitably positioned vinyl halide can undergo Heck-type intramolecular coupling to generate dienes (equations 124 and 125)216,217. When one of the reacting partners in the Heck reaction is a diene, trienes are obtained (equation 126)218. Heck coupling of ally lie alcohols and alkenyl iodides has been employed for the synthesis of vitamin A and related compounds (equation 127)219,220. A similar double Heck reaction on a Cio-diiodide with a Cis-allylic alcohol leads to -carotene as a mixture of isomers (equation 128)209e. 

Double Heck reaction, 42 494 Double layer interface, 30 223-225 Double nucleophilic displacement, capped cyclodextrin, 32 437 Double-pulse method, 38 31 Double recognition models, 32 451 52 Doublet mechanisms, 30 43, 45, 47 Drago parameters, 38 212 Drougard-Decrooq equation, 30 345, 356, 371 Dry evaporation, perovskite preparation, 36 246-247... 

SYNTHESIS OF SYMMETRICAL trans-STILBENES BY A DOUBLE HECK REACTION OF (ARYLAZO)AMINES WITH VINYLTRIETHOXYSILANE trans-4,4 -DIBROMOSTILBENE Benzene, 1,1 -(1,2-ethenediyl)bis[4-bromo-, (E)- using Silane, ethenyltriethoxy- ... 

SYNTHESIS OF SYMMETRICAL frans-STILBENES BY A DOUBLE HECK REACTION OF (ARYLAZO)AMINES WITH VINYLTRIETHOXYSILANE frans-4,4 -DIBROMOSTILBENE... 

A double Heck reaction of a reactant for which /3-hydride elimination is possible was described recently (117). The reaction was catalyzed by Pd(0) with phenanthroline ligand in aqueous media. 

A broad variety of special aldehydes and ketones are easily accessible by Heck-type reactions with allylic alcohols and their homologs [3]. The potential for the synthesis of carbocydic structures is illustrated by the macrocyde 11 [4] which obviously is the product of a fourfold Heck reaction (Scheme 3). A domino process consisting of a double Heck reaction followed by an intramolecular Aldol condensation leads to the annulated ring system 15 [5]. 

An inter- followed by an intra- molecular double Heck reaction features in the synthesis of the xanthene 20 from 2-bromophenyl ether and ethyl acrylate <02TL8559>. 

Heck reaction is a diene, trienes are obtained (equation l26). Heck coupling of allylic alcohols and alkenyl iodides has been employed for the synthesis of vitamin A and related compounds (equation A similar double Heck reaction on a Cio-diiodide with... 

The progress of tandem Heck reactions in organic synthesis [16] led to their first application in the aqueous phase. Hence, a double Heck reaction on a substrate for which /3-hydride elimination is possible results in three tricyclic products (Scheme 1) [17]. 

Double Heck reactions of vicinal ci5 -l,2-dihaloalkenes provide an easy access to (E,Z,E)-1,3.5-hexatrienes, which are valuable building blocks for organic synthesis. t t The first example of a twofold double, that is, essentially a fourfold, Heck reaction with a bis(dibromo)cycloalkene has been conducted on the strained l,2,9,10-tetrabromo[2.2] paia-cyclophane-1,9-diene, which is available in multigram quantities. The Heck reaction proceeded cleanly under phase transfer conditions, as developed by Jeffery, f i to give the tetraalkenylated products in moderate to good yields (Table 8). The resulting bishexatrienes... 

In addition, IMI developed a route to disubstituted benzophenones based on a heterogeneously catalyzed Heck reaction in conjunction with an oxidative cleavage reaction. As an example, the synthesis of 4,4 -difluorobenzophenone, which is used as a monomer for polyether ketones, has been performed by a double Heck reaction of 4-fiuorobromoben-zene with 2-ethylhexyl acrylate. Subsequent oxidative cleavage of the double adduct yields the desired product. ... 

Fukuyama G2 (2009) plan for (+)-lysergic acid double Heck reaction (step 21). 

Botella, L. and Najera, C. (2005) Mono- and jS,jS-double-Heck reactions of a, 8-unsaturated carbonyl compounds in aqueous media. J. Org. Chem., 70, 4360 9. 

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