Henry reaction reviews

The nitro-dldolredcdon between nitrodlkdnes and carbonyl compounds to yieldfi-nitro alcohols was discovered in 1895 by Henry. Since dien, diis reaction has been used extensively in many important syndieses. In view of its significance, diere are several reviews on die Henry reaction." These reviews cover syndiesis of fi-nitro alcohols and dieir applications in organic synthesis. The most comprehensive review is Ref 3, which summarizes the literature before 1970. More recent reviews are Refs. 4 and 5, which summarize literatures on the Henry reaction published until 1990. 

In general, the Henry reaction gives a mixture of diastereomers and enantiomers. The lack of selectivity is due to the reversibility of the reaction and the easy epimerization at the nitro-substituted carbon atom. Existing reviews have hardly mentioned the stereochemistry of the Henry reaction. Recently, Shibasaki has found that the modification of the Henry reaction can control the stereochemistry to give (3-nitro alcohols with high diastereo- and enantio-selectivity.6 In Section 3.3, the progress of the stereoselective Henry reaction and its application to biologically active compounds are discussed. 

The review by Barrett (Ref. 127) documents synthetic application of hetero-substituted nitroalkenes (see also Chapter 4). 1-Chloro-l-nitroalkenes are readily obtained either by the Henry reaction of chloronitromethane with aldehydes or chlorination of l-nitroalkenes. Dauzonne and coworkers have used 1-chloro-l-nitroalkenes for construction of dihydrobenzo-furan or dihydrobenzopyran frameworks. (Eq. 5.83).133... 

The conversion of primary or secondary nitro compounds into aldehydes or ketones is normally accomplished by use of the Nef reaction, which is one of the most important transformations of nitro compounds. Various methods have been introduced forthis transformation (1) treatment of nitronates with acid, (2) oxidation of nitronates, and (3) reduction of nitroalkenes. Although a comprehensive review is available,3 important procedures and improved methods published after this review are presented in this chapter. The Nef reaction after the nitro-aldol (Henry reaction), Michael addition, or Diels-Alder reaction using nitroalkanes or nitroalkenes has been used extensively in organic synthesis of various substrates, including complicated natural products. Some of them are presented in this chapter other examples are presented in the chapters discussing the Henry reaction (Chapter 3), Michael addition (Chapter 4), and Diels-Alder reaction (Chapter 8). 

For a review about nitroaldol and the Henry reaction, see Rosini and Ballini.120... 

For a review of this reaction with respect to nitroalkancs (often called the Henry reaction), see Baer Urbas. in Feuer, Ref. 180, pp. 76-117. See also Rosini Ballini Sorrenti Synthesis 1983, 1014 Matsumoto Angew. Chem. Int. Ed. Engl. 1984,23, 617 Angew. Chem. 96, 599) Eyer Seebach J. Am. Chemr Soc. 1985, 107. 3601. For reviews of the nitroalkenes that are the products of this reaction, see Barrett Graboski Chem. Rev. 1986,66.751-762 Kabalka Varma Org. Prep. Proced. Int. 1987, 19. 283-328. 

The catalytic asymmetric Henry reaction has been reviewed.141,142... 

The catalytic asymmetric Henry reaction has been reviewed.42 Mild and efficient enantioselective nitroaldol reactions of nitromethane with various aldehydes have been catalysed by chiral copper Schiff-base complexes yielding the corresponding adducts with high yields and good enantiometric excess.43,44... 

The Henry reaction or the nitroaldol is a classical reaction where the a-anion of an alkyinitro compound reacts with an aldehyde or ketone to form a p-nitroalcohol adduct. Over the decades, the Henry reaction has been used to synthesize natural products and pharmaceutical intermediates. In addition, asyimnetric catalysis has allowed this venerable reaction to contribute to a plethora of stereoselective aldol condensations. Reviews (a) Ballini, R. Bosica, G. Fiorini, D. Palmieri, A. Front. Nat. Prod. Chem. 2005, 1, 37-41. (b) Ono, N. In The Nitro Group in Organic Synthesis Wiley-VCH Weinheim, 2001 Chapter 3 The Nitro-Aldol (Henry) Reaction, pp. 30-69. (c) Luzzio, F. A. Tetrahedron 2001, 57, 915-945. 

There are several important general reviews on the utility of nitro aliphatic compounds and the Henry reaction in organic synthesis. " Several of these are quite recent reviews and give further evidence for renewed interest in this area of chemistry. 

For a review of the Henry reaction, i.e. the reaction of nitroalkenes with carbonyl compounds, see H. H. Baer and L. Urbas, in The Chemistry of the Nitro and Nitroso Groups , ed. H. Feuer, Interscience, New York,... 

The asymmetric Henry reaction has been reviewed, " and a survey of organocat- 0 alytic enantioselective versions includes recent advances in the emergent domino Michael/Henry protocol. 0... 

Historical perspective C. H. Heathcock, Comp. Org. Syn. 2, 133-179 (1991). General review T. Mukaiyama, Org. React. 28,203-331 (1982). Application of lithium and magnesium enolates C. H. Heathcock, Comp. Org. Syn. 2, 181-238 (1991) of boron enolates B. M. Kim etal, ibid. 239-275 of transition metal enolates I. Paterson, ibid. 301-319. Stereoselective reactions of ester and thioester enolates M. Braun, H. Sacha, J. Prakt. Chem. 335,653-668 (1993). Review of asymmetric methodology A. S. Franklin, I. Paterson, Contemp. Org. Syn. 1,317-338 (1994). Cf. Claisen-Schmidt Condensation Henry Reaction Ivanov Reaction Knoevenagel Condensation Reformatskv Reaction Robinson Annulation. 

The use of Mannich and aza-Henry reactions to synthesize / -nitroamines has been reviewed." ... 

The scope, limitations and mechanisms of asymmetric Henry reactions catalysed by transition metal complexes have been reviewed. ... 

The Henry reaction is a base-catalyzed C-C bond-forming reaction between nitroalkanes and aldehydes or ketones. It is similar to the aldol addition, and is also referred to as the nitroaldol reaction. Since its discovery in 1895 [1] the Henry reaction has become one of the most useful reactions for the formation of C-C bonds, and most particularly for the synthesis of P-nitroalcohol derivatives [2]. The general features of this reaction are (i) the potential offered by the nitro and hydroxyl groups on the products for transformation into other compound families such as P-amino alcohols, P-amino acids, or nitroalkenes (ii) only a catalytic amount of base is required (iii) up to two contiguous stereogenic centers may be created in a single step concomitantly to the C-C bond formation. Several recent reviews with a focus on the asymmetric Henry reaction and its applications have appeared [3j. 

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