Etherification palladium

Although palladium catalysts have played the most prominent role in this area, other metals have also been found to catalyze allylic etherification reactions, often providing complementary stereochemical outcomes. A few ruthenium catalyst systems have been used for the O-allylation of phenols,143,144 including an enantioselective version utilizing [Cp Ru(MeCN)3]PF6 that provides promising ee s, albeit with diminished control of regioselectivity (Equation (25)).145... 

As compared to the esterification of sucrose, cataly tic etherification of sucrose provides another family of non-ionic surfactants that are much more robust than sucrose esters in the presence of water. Synthesis of sucroethers can be achieved according to two processes (1) the ring opening of epoxide in the presence of a basic catalyst and (2) the telomerization of butadiene with sucrose using a palladium-phosphine catalyst. 

C-M bond addition, for C-C bond formation, 10, 403-491 iridium additions, 10, 456 nickel additions, 10, 463 niobium additions, 10, 427 osmium additions, 10, 445 palladium additions, 10, 468 rhodium additions, 10, 455 ruthenium additions, 10, 444 Sc and Y additions, 10, 405 tantalum additions, 10, 429 titanium additions, 10, 421 vanadium additions, 10, 426 zirconium additions, 10, 424 Carbon-oxygen bond formation via alkyne hydration, 10, 678 for aryl and alkenyl ethers, 10, 650 via cobalt-mediated propargylic etherification, 10, 665 Cu-mediated, with borons, 9, 219 cycloetherification, 10, 673 etherification, 10, 669, 10, 685 via hydro- and alkylative alkoxylation, 10, 683 via inter- andd intramolecular hydroalkoxylation, 10, 672 via metal vinylidenes, 10, 676 via SnI and S Z processes, 10, 684 via transition metal rc-arene complexes, 10, 685 via transition metal-mediated etherification, overview,... 

Another important etherification is the palladium-catalyzed telomerization of glycerol with butadiene yielding octadienyl ethers of glycerol, which can be used as starting materials for detergents [51, 52]. 

Similarly, chelation-assisted palladium-catalyzed oxidative functionalizations of C—H bonds with, for example, hypervalent iodine(III) reagents turned out to be particularly valuable. These protocols allowed for, inter alia, regioselective acetoxyla-tion or etherification of aromatic and aliphatic C— H bonds [17-19], and also halogenations of arenes (Scheme 9.3) [20, 21]. 

Etherification of carbohydrate is an important reaction. The two-phase reaction of butadiene with saccharose by an aqueous palladium complex catalyst increases the reaction yield of the desired ether products (Eq. 5) [21]. 

Scheme 10 accounts for the Pd(OAc)2-catalysed allylic oxidation of CM-vinylsilanes by Phl(OAc)2 to give corresponding cis- and frani-vinylsilane products (63) and (66) via initial formation of a 7r-allyl palladium intermediate (61), which changed to anti-TT-allylpalladium (62) in the presence of benzoquinone. The rrani-vinylsilanes were resistant to oxidation. Also described is the intra-molecular allylic C-H etherification of c -vinylsilanes to produce five- and six-membered oxygen heterocycles that retain the vinyl silane functionality. ... 

Etherification Cross-Coupling Reactions 2.11.3.1 With Palladium... 

The following discussion focuses on the synthesis of aromatic heterocycles where a key palladium- or copper-catalyzed aryl halide (or equivalent) amination, etherification or thioetherification process is employed. Annulative routes utilizing anilines and related compounds with alkynes (Larock type) are also considered. Routes that do not lead to aromatic products or that rely on the functionalization of preexisting heterocycles have been discounted. Similarly, the synthesis of heterocycles via TT-allylpalladium chemistry or intramolecular cyclization of palladium Tr-olefin and TT-alkyne complexes is not featured. The discussion is structured predominantly around the type of bond being formed (C—N, C—O, or C—S) and is classified further by heterocycle type. Intramolecular and intermolecular C—X bond formations as well as tandem catalytic processes leading to aromatic heterocycle products are all discussed. 

By definition, palladium- and copper-catalyzed aryl amidation, aryl etherification, and aryl thioetherification reactions are transformations designed to construct bonds between heteroatoms and aromatic rings. Thus, it is perhaps not surprising that these... 

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