III. Foldamer Research 3910 A. Overview 3910 B. Motivation 3910 C. Methods 3910 D. General Scope 3912 IV. Peptidomimetic Foldamers 3912 A. The R-Peptide Family 3913 1. Peptoids 3913 2. N,N-Linked Oligoureas 3914 3. Oligopyrrolinones 3915 4. Oxazolidin-2-ones 3916 5. Azatides and Azapeptides 3916 B. The â-Peptide Family 3917 1. â-Peptide Foldamers 3917 2. R-Aminoxy Acids 3937 3. Sulfur-Containing â-Peptide Analogues 3937 4. Hydrazino Peptides 3938 C. The γ-Peptide Family 3938 1. γ-Peptide Foldamers 3938 2. Other Members of the γ-Peptide Family 3941 D. The δ-Peptide Family 3941 1. Alkene-Based δ-Amino Acids 3941 2. Carbopeptoids 3941 V. Single-Stranded Abiotic Foldamers 3944 A. Overview 3944 B. Backbones Utilizing Bipyridine Segments 3944 1. Pyridine−Pyrimidines 3944 2. Pyridine−Pyrimidines with Hydrazal Linkers 3945

A field guide to foldamers.

Asymmetric 1,3-Dipolar Cycloaddition Reactions

The tridecamer d(A-A-T-G-G-T-A-A-A-A-T-G-G), which is complementary to 13 nucleotides of the 3'- and 5'-reiterated terminal sequences of Rous sarcoma virus 35S RNA, was added to chick embryo fibroblast tissue cultures infected with Rous sarcoma virus. Inhibition of virus production resulted. The inference emerges that the tridecamer and its counterpart with blocked 3'- and 5'-hydroxyl termini enter the chick fibroblast cells, hybridize with the terminal reiterated sequences at the 3' and 5' ends of the 35S RNA, and interfere with one or more steps involved in viral production and cell transformation. Likely sites of action are (i) the circularization step of the proviral DNA intermediate, and (ii) the initiation of translation, the latter being described in the following communication [Stephenson, M. L. & Zamecnik, P. C. (1978) Proc. Natl. Acad. Sci. USA 75, 285--288].

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Inhibition of Rous sarcoma virus replication and cell transformation by a specific oligodeoxynucleotide

The substituted indole nucleus [indole is the acronym from indigo (the natural dye) and oleum (used for the isolation)] is a structural component of a vast number of biologically active natural and unnatural compounds. The synthesis and functionalization of indoles has been the object of research for over 100 years, and a variety of well-established classical methods are now available, to name a few of them, the Fisher indole synthesis, the Gassman synthesis of indoles from N-halo-anilines, the Madelung cyclization of N-acyl-o-toluidines, the Bischler indole synthesis, the Batcho-Leimgruber synthesis of indoles from o-nitrotoluenes and dimethylformamide acetals, and the reductive cyclization of o-nitrobenzyl ketones.1 In the last 40 years or so, however, palladiumcatalyzed reactions, generally tolerant of a wide range of functionalities and therefore applicable to complex molecules, have achieved an important place in the arsenal of the practicing organic chemist. Since the invention of an industrial process for the palladium-catalyzed production of acetaldehyde from ethylene in the presence of PdCl2 and CuCl2, an everincreasing number of organic transformations have been based on palladium catalysis. Almost every area of the organic synthesis has been deeply influenced by the profound potential of this versatile transition metal, modifying the way organic chemists design and realize synthetic processes.2,3 Because of its catalytic nature, palladium-catalyzed synthesis can provide access to fine chemicals, agrochemical and pharmaceutical intermediates, and active ingredients in fewer steps and with less waste than classical † In memory of Prof. Bianca Rosa Pietroni, a colleague and very close friend. * To whom correspondence should be addressed. Phone: + 39 (06) 4991-2785. Fax: + 30 (06) 4991-2780. E-mail: sandro.cacchi@ uniroma1.it. 2873 Chem. Rev. 2005, 105, 2873−2920

Synthesis and functionalization of indoles through palladium-catalyzed reactions

Palladium-catalyzed carbonylation reactions of aromatic halides in the presence of various nucleophiles have undergone rapid development since the pioneering work of Heck and co-workers in 1974, such that nowadays a plethora of palladium catalysts are available for different carbonylative transformations. The carboxylic acid derivatives, aldehydes, and ketones prepared in this way are important intermediates in the manufacture of dyes, pharmaceuticals, agrochemicals, and other industrial products. In this Review, the recent academic developments in this area and the first industrial processes are summarized.

Palladium-catalyzed carbonylation reactions of aryl halides and related compounds.

The use of arylsulfonyltriazoles for the synthesis of oligonucleotides by the triester approach.

Improved triester approach for the synthesis of pentadecathymidylic acid.

A modified triester method has been developed for the synthesis of oligonucleotides starting from mononucleosides as more economical starting materials. A pentadecanucleotide has been successfully prepared.

A Modified Triester Method for the Synthesis of Deoxyribopolynucleotides

The synthesis and in vitro anti-HIV activity of two new racemic nucleoside analogues are described; namely, 9-[c-4,t-5-bis(hydroxymethyl)cyclopent-2-en-r-1-yl]-9H-adenine (12) and its guanine analogue 18. While the latter (18) showed no activity, the therapeutic index of the former (12) was 200 and comparable to that (400) of carbovir. One enantiomer of 12 may be viewed as an analogue of carbocyclic oxetanocin and the other as an analogue of carbovir. Hence, these results indicate that one or both of the individual enantiomers of 12 could serve as candidates or lead compounds for the development of anti-AIDS agents.

Synthesis and anti-HIV activity of 9-[c-4,t-5-bis(hydroxymethyl)cyclopent-2-en-r-1-yl]-9H-adenine.

Synthesis of chiral spiro 3-oxazolin-5-one 3-oxides (chiral nitrones) via a nitrosoketene intermediate and their asymmetric 1,3-dipolar cycloaddition reactions leading to the EPC synthesis of modified amino acids

Nobuya Katagiri

Papers

The use of arylsulfonyltriazoles for the synthesis of oligonucleotides by the triester approach.

Improved triester approach for the synthesis of pentadecathymidylic acid.

A Modified Triester Method for the Synthesis of Deoxyribopolynucleotides

Synthesis and anti-HIV activity of 9-[c-4,t-5-bis(hydroxymethyl)cyclopent-2-en-r-1-yl]-9H-adenine.

Synthesis of chiral spiro 3-oxazolin-5-one 3-oxides (chiral nitrones) via a nitrosoketene intermediate and their asymmetric 1,3-dipolar cycloaddition reactions leading to the EPC synthesis of modified amino acids