Cycloaddition reactions overview

Giuliano R. M. Cycloaddition Reactions in Carbohydrate Chemistry. An Overview... 

In this chapter we provide an overview of studies originating from the above work and directed at the design and development of three new metal-catalyzed cycloaddition reactions, namely the [5+2] cycloaddition of vinylcyclopropanes (VCPs) and rc-systems, the [6+2] cycloaddition of vinylcyclobutanones and re-systems, and the three-component, [5+2+1] cycloaddition of VCPs, rc-systems, and CO. These new reactions provide fundamentally new approaches to a range of problems in seven- and eight-membered ring synthesis. 

The syntheses of diazetidines are known to proceed via a [2+2] cycloaddition reaction of alkene derivatives with azo compounds. A comprehensive literature overview has been provided in CHEC-II(1996) <1996CHEC-II(1B)911>. This chapter compiles some of the new synthetic methods and examples reported after 1994. 

In this chapter we have attempted to summarize recent trends in nitrile oxide cycloaddition reactions of alkenes. We hope that this overview will stimulate and encourage continued work in the field. 

As the focus of this chapter is on the synthetic utility of the rDA reaction, an overview of mechanism is beyond the scope of this review however, the subject has beoi reviewed previously. Structural and medium effects on the rate of the rDA reaction are of prime importance to their synthetic utility, and therefore warrant discussion here. A study of steric effects cm the rate of cycloreversicHi was the focus of early work by Bachmann and later by Vaughan. The effect of both diene and dioiophile substituticHi on Ae rate of the rDA reaction in anthracene cycloadducts has been reported in a study employing 45 different adducts. If both cycloaddition and cycloreversion processes are fast on the time scde of a given experiment, reversibility in the DA reaction is observed. Reversible cycloaddition reactions involving anthracenes, furans, fulvenes and cyclopentadienes are known. Herndon has shown that the well-known exception to the endo rule in tiie DA reaction of furan with maleic anhydride (equation 2) occurs not because exo addition is faster than endo addition (it is not), but because cycloreversion of the endo adduct is about 10 000 times faster than that of the exo adduct. ... 

For a review, see Giuliano, RM, Cycloaddition reactions in carbohydrate chemistry — an overview. In Cycloaddition Reactions in Carbohydrate Chemistry, Giuliano, RM, Ed., American Chemical Society, Washington, DC, pp. 1-23, 1992. 

Giuliano, R. M. Cycloaddition reactions in carbohydrate chemistry. An overview. ACS Symp. Ser. 1992,494,1-23. 

Herein an overview of the most relevant approaches for the synthesis of un-natiual heterocycles of biological and industrial potential from carbohydrates is presented the natiual heterocycles have been previously reviewed [6]. This review is hmited to heterocycles with one or more of their carbon skeletons derived from carbohydrate precursors—those formed by cycloaddition reactions are not included. Also, carbohydrates with strained ring systems, oxiranes, aziridines, and thiiranes have aheady been reviewed and are not included herein [20]. The synthetic approaches for the reviewed heterocycles are divided according to the size of the heterocychc rings and the number of hetero atoms in the ring. The bicyclic ring systems are included under the smaller ring of their skeleton. 

A special mention deserves the overview Nick Turro has published of his work in physical organic, organic supramolecular and spin chemistry during his five decades carrier at Columbia. A tutorial review has been published on the utility of photolabile protecting groups in chemical synthesis and in biology. A wide scope crytical review has been devoted to the 2 + 2 cycloaddition reaction involving allenes and includes several photoehemical examples. ... 

This chapter gives an overview about applications of cycloaddition reactions to study nucleic acids. These cycloaddition reactions are typically grouped under the heading click chemistry despite varying other chemistries, and an enormous amount of different applications in the context of DNA and RNA have been found so far. Only selected recent implementations for cycloaddition reactions on nucleic acids can be presented in the limited scope of this chapter. Today s click reactions, as first defined by Sharpless et al. [1], are associated with biocompatibility, fast reaction kinetics and bio-orthogonality. 

The following graphic (Fig. 1) gives an overview about various cycloaddition reactions used for nucleic acid functionalization. The individual reactions are discussed in detail below. 

We now present an overview of the basic types of organic photochemical reactions. We begin with acid-base reactions, and then turn to reactions of hydrocarbon tt systems, such as olefin isomerizations, cycloaddition reactions, and the di-rr-methane rearrangement. We then study "heteroatom" photochemistry, the photoreactions of carbonyls and nitrogen-containing chromophores. 

Even though the CuAAC is a rather new reaction, more than 800 publications on Cu AAC chck chemistry has been pubhshed (May 2008), and it has been extensively reviewed. The focus of this chapter will be on azides in 1,3-dipolar cycloaddition reactions, mainly catalyzed by transition metals, in peptide chemistry. Protein ligation and protein modification by dipolar cycloaddition reactions has been reviewed and will not be included. Angell and Burgess published an excellent review on peptidomimetics generated by CuAAC in early 2007 with a thorough overview of the field and since then more than twenty new pubhcations describing dipolar cycloaddition reactions in peptide chemistry have appeared. 

KS High pressure promotes a great number of cycloaddition reactions yielding heterocyclic products, which could not be prepared in conventional reaction conditions. The structure of prepared products varies in their complexity from simple to densely substituted polycyclic skeleton of significant biological interests. This chapter offers an overview of the recent advances in the field of application of high pressures in organic synthesis. 

During the last decade, numerous cobalt-substituted 1,3-dienes have been synthesized and the rates, regioselectiv-ities, and stereoselectivities of their reactions with dienophiles in [4 - - 2]-cycloaddition reactions were examined (Scheme Few reviews gave an overview of the results obtained in this field. The dienylcobalt... 

Abstract The use of organoaluminum-based Lewis acids (A1R X3 R = alkyl, alkynyl, X = halide or pseudohalide) in the period 2000 to mid-2011 is overviewed with a focus on (1) stoichiometric reactions in which one of the organoaluminum substituents is transferred to the substrate (e.g., the opening of epoxides, 1,2-additions to carbonyl compounds, coupling with C-X, and Reissert chemistry) and (2) asymmetric, often catalytic, reactions promoted by Lewis acid catalysts derived from organoaluminum species (e.g., use of auxiliaries with alanes, Diels-Alder, and related cycloaddition reactions, additions to aldehydes and ketones, and skeletal rearrangement reactions). 

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