Addition reactions heteroatom nucleophiles

Conjugate Addition of Heteroatom Nucleophiles and Subsequent Nef Reaction... 

Most synthetically useful radical addition reactions pair nucleophilic radicals with electron poor alkenes. In this pairing, the most important FMO interaction is that of the SOMO of the radical with the LUMO of the alkene.36 Thus, many radicals are nucleophilic (despite being electron deficient) because they have relatively high-lying SOMOs. Several important classes of nucleophilic radicals are shown in Scheme IS. These include heteroatom-substituted radicals, vinyl, aryl and acyl radicals, and most importantly, alkyl radicals. 

The reverse reaction, i.e., the addition of water to the heterocumulene B with formation of carbonic acid derivatives A, is also known. With very few exceptions this reaction occurs spontaneously with catalysis by an acid or base. The hydration of a heterocumulene is a special example of an entire class of heterocumulene reactions, namely the addition of heteroatom nucleophiles H-Het3 (you have already come across such a reaction briefly in Section 6.1.1 in the context of the DCC activation of carboxylic acids). Occasionally, this addition... 

Additions of Heteroatom Nucleophiles to Carbonyl Compounds and Subsequent Reactions—Condensations of Heteroatom Nucleophiles with Carbonyl Compounds... 

Addition of Heteroatom Nucleophiles to Carbonyl Compounds in Combination with Subsequent SN1 Reactions of the Primary Product Acetalizations... 

The former chapter Additions of Heteroatom Nucleophiles to Heterocumulenes, Additions of Heteroatom Nucleophiles to Carbonyl Compounds and Follow-up Reactions has been spht into two separate chapters into Chapter 8 Carbonic Acid Derivatives and Heterocumulenes and Their Interconversion , whose systematic organization should represent a particularly valuable learning aid, and into Chapter 9 Additions of Het-eroatom Nucleophiles to Carbonyl Compounds and Follow-up Reactions—Condensations of Heteroatom Nucleophiles with Carbonyl Compounds. ... 

Besides the Michael addition of heteroatomic nucleophiles initiating cyclocondensations, acceptor substituted unsaturated systems can also be reacted with carbon nucleophiles stemming from aldehydes in the sense of an umpolung, generally referred to as the Stetter reaction [244-246]. This process is organocatalytic and furnishes in turn 1,4-dicarbonyl compounds, intermediates that are well suited for Paal-Knorr cyclocondensations giving rise to furans or pyrroles. Among numerous heterocycles furans and pyrroles have always been the most prominent ones since they constitute important classes of natural products [247-249], of synthetic... 

Two systems have been developed to the level of useful organic synthesis methodology spontaneous coordination of the alkene to Pd and the preparation of discrete Cp(CO)2Fe-alkene cationic complexes. With the Pd system, efficient catalytic processes have been developed for the addition of heteroatom nucleophiles, while the coupling with carbon nucleophiles is mainly relegated to stoichiometric reactions these two topics will be presented separately. In the iron series, the reactions involve stable intermediates and are invariably not amenable to catalysis. 

A Michael Reaction Coupled to a Photochemical Cyclisation Copper Again Michael Additions of Heteroatom Nucleophiles... 

The organocatalytic asymmetric conjugate addition of heteroatom nucleophiles to different electrophilic olefins has become a very popular reaction during the last few years. Different nitrogen, oxygen, sulfur, and selenium nucleophilic species have been successfully used leading to enantiomerically emiched heterofunctionalized derivatives. 

Chiral aldehydes 28 with a-stereocenters undergo addition reactions with nucleophiles with predictable stereoselectivity patterns. The Felkin-Anh model proposes that the nucleophile approaches anti to the a-substituent that is either the largest or a heteroatom, and approaches the aldehyde via the... 

The addition of heteroatom nucleophiles to Q , -unsaturated carbonyl compounds has also been promoted using TBDMS triflate. An intermolecular aza-double Michael reaction has been developed as a route to functionalized piperidin-2-ones (eq 27). Due to its relative ease of handling, TBDMS triflate was generally preferred to TMSI-HMDS as an additive in such reactions. 

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