Organic synthesis electrophilic reagents

Nucleophilic substitution reaction is another class of important transformations that organosilicon reagents play key roles in organic synthesis. Electrophiles such as acyl and alkyl halides activated by a Lewis acid in a stoichiometric amount readily react with silyl enol ethers, allylsilanes, and alkenylsilanes. ... 

Application of 7r-allylpalladium chemistry to organic synthesis has made remarkable progress[l]. As deseribed in Chapter 3, Seetion 3, Tt-allylpalladium complexes react with soft carbon nucleophiles such as maionates, /3-keto esters, and enamines in DMSO to form earbon-carbon bonds[2, 3], The characteristie feature of this reaction is that whereas organometallic reagents are eonsidered to be nucleophilic and react with electrophiles, typieally earbonyl eompounds, Tt-allylpalladium complexes are electrophilie and reaet with nucleophiles such as active methylene compounds, and Pd(0) is formed after the reaction. 

Abstract Bismuth(III) salts are currently considered efficient and ecofriendly reagents and catalysts for the development of new applications in organic synthesis. The preparation of bismuth(III) triflate and its analogues is reviewed as well as some of their applications to the synthesis of bulk chemicals via electrophilic addition and cyclization reactions. The use of bismuth(III) salts in the development of new chemical processes involving steroids and terpenes as substrates is also discussed. 

This chapter is an update (2003 to present) of the main applications of Bi(III) Lewis acids in organic synthesis developed and, in some cases, co-developed, by French and Portuguese research groups. Thus, in this chapter, the preparation of Bi(III) catalysts and their application to chemical transformations ranging from electrophilic addition to cyclization reactions, will be reviewed. The development of new environmentally friendly chemical processes, using Bi(III) reagents and catalysts, with direct application to steroid chemistry and related compounds will also be considered. 

There is a variety of reagents that undergo carbene-related transformations that do not fit into the categories of nucleophilic and electrophilic metal carbenes described earlier. Those that are the most versatile for organic synthesis, like the Tebbe... 

Acyliron complexes have found many applications in organic synthesis [40]. Usually they are prepared by acylation of [CpFe(CO)2] with acyl chlorides or mixed anhydrides (Scheme 1.13). This procedure affords alkyl, aryl and a,P-unsaturated acyliron complexes. Alternatively, acyliron complexes can be obtained by treatment of [Fe(C5Me5)(CO)4]+ with organolithium reagents, a,P-Unsaturated acyliron complexes can be obtained by reaction of the same reagent with 2-alkyn-l-ols. Deprotonation of acyliron complexes with butyllithium generates the corresponding enolates, which can be functionalized by reaction with various electrophiles [40]. 

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