Catalytic asymmetric Diels-Alder

Catalytic asymmetric Diels-Alder reactions are presented by Hayashi, who takes as the starting point the synthetically useful breakthrough in 1979 by Koga et al. The various chiral Lewis acids which can catalyze the reaction of different dieno-philes are presented. Closely related to the Diels-Alder reaction is the [3-1-2] carbo-cyclic cycloaddition of palladium trimethylenemethane with alkenes, discovered by Trost and Chan. In the second chapter Chan provides some brief background information about this class of cycloaddition reaction, but concentrates primarily on recent advances. The part of the book dealing with carbo-cycloaddition reactions is... 

I 1 Catalytic Asymmetric Diels-Alder Reactions 1.2.3.1 Aluminum... 

Scheme 7. Catalytic asymmetric Diels-Alder approach to enantiomerically pure iodolactone 32.

Kagan H. B., Riant O. Catalytic Asymmetric Diels-Alder Reactions Chem. Rev. 1992 92 1007-1019... 

Recently, catalytic asymmetric Diels-Alder reactions have been investigated. Yamamoto reported a Bronsted-acid-assistcd chiral (BLA) Lewis acid, prepared from (R)-3-(2-hydroxy-3-phcnylphenyl)-2,2 -dihydroxy-1,1 -binaphthyl and 3,5A(trifluoromethy I) - be nzeneboronic acid, that is effective in catalyzing the enantioselective Diels-Alder reaction between a,(3-enals and various dienes.62 The interesting aspect is the role of water, THF, and MS 4A in the preparation of the catalyst (Eq. 12.19). To prevent the trimerization of the boronic acid during the preparation of the catalyst, the chiral triol and the boronic acid were mixed under aqueous conditions and then dried. Using the catalyst prepared in this manner, a 99% ee was obtained in the Diels-Alder reaction... 

Asymmetric Diels-Alder reactions have been performed by using either chiral dienophiles or chiral dienes in the presence or the absence of catalysts.47 The progress in this field is remarkable catalytic asymmetric Diels-Alder reactions are generally carried out either by the use of chiral dienophiles or by the use of chiral dienes. Here, the reactions of chiral nitroalkenes with dienes or the reactions of nitroalkenes with chiral dienes are discussed. Many different chiral auxiliaries are now available, and some of them have been used in asymmetric Diels-Alder reactions of nitroalkenes. 

This chapter focuses on some typical examples, starting with the usual cycloaddition reactions and then the catalytic asymmetric Diels-Alder reactions, hetero Diels-Alder reactions, retro Diels-Alder reactions, and intramolecular... 

There are few transformations that can, in a single stroke, provide the structural and stereochemical complexities that are attained through a Diels-Alder cydoaddition. It is little surprise then that numerous studies have appeared in the past decade that aim to develop a catalytic asymmetric Diels-Alder process. It is only in a few instances, however, that these catalytic asymmetric protocols have been applied to target-oriented synthesis. Several impres-... 

Modifications to the architecture of the imidazolidinone catalyst provided the fnryl derivative (20) which proved to be a powerfnl catalyst for the catalytic asymmetric Diels-Alder cycloaddition of simple a,P-unsaturated ketones [50]. Although... 

A catalytic asymmetric Diels-Alder reaction was developed by using 3-(3-borylpropenoyl)oxazolidin-2-ones 146. In the reactions of butadiene, isoprene, or 2-methyl-l,3-pentadiene and 146, in the presence of a chiral titanium catalyst 147, the cyclohexene derivatives 148 were formed. 

With Tartrate-Derived Chiral 1,4-Diol/Ti Complexes A catalytic asymmetric Diels-Alder reaction is promoted by the use of a chiral titanium catalyst prepared in situ from (Pr O TiC and a tartrate-derived (2.R,3.R)-l,l>4,4-tetraphenyl-2,3-0-(l-phenylethylidene)-l,2,3,4-butanetetrol. This chiral titanium catalyst, developed by Narasaka, has been successfully executed with oxazolidinone derivatives of 3-borylpropenoic acids as P-hydroxy acrylic acid equivalents [40] (Eq. 8A.21). The resulting chiral adduct can be utilized for the first asymmetric total synthesis of a highly oxygenated sesquiterpene, (-i-)-Paniculide. 

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