C-heteroatom bond formation

Cobalt-catalyzed C—C and C-heteroatom bond formation in transformations of heterocycles 97SL876. 

Examples of "very tnixed"-metal cluster-assisted C-heteroatom bond formation are still rare, with both literature extant examples involving coupling of bridging phosphido ligand with a C-ligand. Phosphido, hydrido, and alky tie were assembled stereospecilically to afford PPh2(( /.v-CR=CHR) (Fig. 29),-" while an unusual... 

Cathodic substitution stands for C,C bond or C, heteroatom bond formation with cathodically generated anions. The question of regioselectivity is encountered in the reaction of such anions with allyl halides (path a) or in the reaction of allyl anions generated in an ECE process from allyl halides (path b). Cathodic reductive silylation of an allyl halide proceeds regioselectively at the less substituted position (Fig. 15) [91]. From the reduction potentials of the halides it is proposed that the reaction follows path b. 

This chapter mainly concerns common rearrangements of organolithium compounds which are synthetically valuable in terms of a C—C bond or C—heteroatom bond formation. 

Beletskaya, I. P. Palladium Catalysed C-C and C-heteroatom Bond Formation Reactions, Pure Appl. Chem. 1997, 69, 471-476. 

Pd-catalyzed reactions, 9, 431 with pentaarylantimonys, 9, 430 with tetraorganylantimony(V) compounds, 9, 429 in C-heteroatom bond formations, 9, 432 in Friedel-Crafts acylation, 9, 433 Antimony donor ligands in iron carbonyls, 6, 57... 

Barbier-type reactions, 9, 433 in catalyzed C-C bond formation, 9, 438 in C-C bond formations, 9, 435 in C-heteroatom bond formations, 9, 440 with copper catalysts, 9, 442 non-catalyzed reactions, 9, 443 miscellaneous reactions, 9, 444 in oxidations, 9, 443 in reduction reactions, 9, 444 Bismuth(V) compounds... 

Bismuthonium salts in C-C bond formation, 9, 446 in C-heteroatom bond formation, 9, 449 Bismuth ylides... 

Keywords. C-heteroatom bond formation, Aryl-A3-iodanes, Iodonium salts, Sulfonyliminoiodanes, Hypervalent iodine... 

The formation of carbon-heteroatom bonds can be effected by reactions of hypervalent iodine reagents with a wide range of organic substrates and inorganic nucleophiles, and represents one of the most popular applications of organoiodine(III) compounds [1-10]. Except for C-I(III) bond forming reactions used for the synthesis of iodanes and iodonium salts, C-heteroatom bond formation is almost always accompanied by reduction of the hypervalent iodine reagents to iodine(I) compounds. 

The use of aryl-A3-iodanes for C-heteroatom bond formation at the a-carbon atoms of ketones and / -dicarbonyl compounds, and related transformations of silyl enol ethers and silyl ketene acetals, has been exhaustively summarized in recent reviews (Scheme 27) [5,8]. Reactions of this type are especially useful for the introduction of oxygen ligands (e. g., L2 = OH, OR, OCOR, 0S02R, OPO(OR)2), and have been extensively utilized for the synthesis of a-sulfonyl-oxy ketones and a-hydroxy dimethyl ketals. 

The use of diaryliodonium salts for direct arylations of nucleophilic species is a well-established practice. Examples of C-heteroatom bond formation by this approach, including uncatalyzed arylations of dialkyl phosphite, thiocarboxy-late, arylthiosulfonate, dialkyl phosphorothiolate, arylselenolate, and aryltel-lurolate salts with symmetrical diaryliodonium halides, are shown in (Scheme 40) [110-115]. 

For recent reviews on organocatalysis including, for example, C-C and C-heteroatom bond formation, see ... 

The most relevant results regarding the SRN1 substitutions have been extensively reviewed [1-5] consequently, in this chapter we indude only the most recent and major representative synthetic examples in the aromatic system, relating to C—C and C-heteroatom bond formation with sulfur and tin nudeophiles, and ring-dosure reactions. 

Silver salts or reagents have received much attention in preparative organic chemistry because they are useful catalysts for various transformations involving C-G and C-heteroatom bond formation.309 Especially, the silver(i)/ BINAP (2,2 -bis(diphenylphosphino)-l,T-binaphthalene) system is a very effective catalyst for a variety of enantio-selective reactions, including aldol, nitroso aldol, allylation, Mannich, and ene reactions. Moreover, silver salts are known to efficiently catalyze cycloisomerization and cycloaddition reactions of various unsaturated substrates. Recently, new directions in silver catalysis were opened by the development of unique silver complexes that catalyze aza-Diels-Alder reactions, as well as carbene insertions into C-H bonds. 

When the process leads to C-heteroatom bond formation, then the nucleophile is an appropriate heteroatom, either anionic (-X ) or neutral (-XH) ... 

Typical Ring Synthesis of a Pyrrole Involving Only C-Heteroatom Bond Formation... 

I.5.8.4. Additions with C-C/C-Heteroatom Bond Formation (Heterocarboration) 1.5.8.4.1. Carbohydroxylation, Carboalkoxylation and Carbocarboxylation... 

MacGregor SA, Neave GW, Smith C (2003) Theoretical studies on C-heteroatom bond formation via reductive elimmation from group 10 M(PH3)2(CH3)(X) species (X = CH3, NH2, OH, SH) and the determination of metal-X bond strengths using density functional theory. Faraday Discuss 124 111-127... 

In this book, we try to give an overview of the field of organocatalysis with particular emphasis on later developments in the field. First, we will introduce the different activation modes and catalysts. Next, we show a different approach of organocatalysis not based on the different activation modes, but based on the nature of the bond formed. From C-C bond forming reactions to C-heteroatom bond formation through cascade, multicomponent reactions, we will try to give a clear of the state-of-the-art picture of this field. 

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