Optically Active Aromatic and Heteroaromatic α-Amino Acids by a One-Pot Catalytic Enantioselective Addition of Aromatic and Heteroaromatic C−H Bonds to α-Imino Esters

Saaby, Steen; Bayón, Pau; Aburel, Pompiliu S.; Jørgensen, Karl Anker

doi:10.1021/jo0256787

Cited by 97 publications

(33 citation statements)

References 39 publications

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“…Organometallic chemists have focused much attention on developing 'C-H activation' strategies, whereby a highly reactive metal complex inserts into a C-H bond, activating the system for subsequent transformations [7][8][9] . One of the major challenges associated with this chemistry has been to render it catalytic in the metal complex 10 .…”

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confidence: 99%

Catalytic C–H functionalization by metal carbenoid and nitrenoid insertion

Davies

Manning

2008

Nature

2,152

812

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Novel reactions that can selectively functionalize carbon-hydrogen bonds are of intense interest to the chemical community because they offer new strategic approaches for synthesis. A very promising 'carbon-hydrogen functionalization' method involves the insertion of metal carbenes and nitrenes into C-H bonds. This area has experienced considerable growth in the past decade, particularly in the area of enantioselective intermolecular reactions. Here we discuss several facets of these kinds of C-H functionalization reactions and provide a perspective on how this methodology has affected the synthesis of complex natural products and potential pharmaceutical agents.I n 2006, 31 new chemical entities were introduced to the world pharmaceutical market and 2,075 molecules were in phase I or II of clinical development 1 . The majority of these were smallmolecule (relative molecular mass ,1,000) organic compounds 2 . As knowledge about the specific interactions of drugs in vivo increases, often so does the structural complexity of new drug targets. A major obstacle to the development of such drugs is the difficulty associated with synthesizing large quantities in an economical fashion, because complex multi-step syntheses are usually required. In the general media, it is often overlooked that the accessibility of the components required for these new treatments will often govern their eventual success or failure. Likewise, a design element of any pharmaceutical agent is the expectation that the target compounds can be made economically. Therefore, new strategies for synthesis can become enabling technologies, making available new targets and materials that would have been previously out of range. For example, new methodologies such as metal-catalysed crosscoupling 3 and olefin metathesis 4-6 have rapidly become central transformations in the synthesis of new pharmaceutical agents. Selective C-H functionalization is a class of reactions that could lead to a paradigm shift in organic synthesis, relying on selective modification of ubiquitous C-H bonds of organic compounds instead of the standard approach of conducting transformations on pre-existing functional groups. The reactive sites in each type of transformation are very different, as illustrated in Fig. 1.The many opportunities associated with C-H functionalization has made this field an active area of research. Organometallic chemists have focused much attention on developing 'C-H activation' strategies, whereby a highly reactive metal complex inserts into a C-H bond, activating the system for subsequent transformations 7-9 . One of the major challenges associated with this chemistry has been to render it catalytic in the metal complex 10 . A partial solution to this problem has been to use neighbouring functionality to direct less reactive metal complexes to the site for functionalization. Numerous reviews have been written about this method for C-H functionalization [11][12][13][14][15][16][17] . Here, however, we highlight another approach, in which a divalent c...

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confidence: 99%

Catalytic C–H functionalization by metal carbenoid and nitrenoid insertion

Davies

Manning

2008

Nature

2,152

812

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“…There are no characteristic hydrogen bonding patterns, but interactions between the amide groups are common, and these are frequently corroborated by weaker C-H· · · O interactions in various ways. Figure 35 shows a special example for a methyl ester (GUTCAZ) [153] where four weak contacts (including the N-H· · · O=C < hydrogen bond) build a tape-like motif along a 5.78 Å crystallographic axis.…”

Section: N-and C-protected Amino Acidsmentioning

confidence: 99%

“…(a) Schematic drawing of (5-benzylidene-2,5-dihydrofuran-2-yl)(methoxycarbonylamino)acetic acid methyl ester (GUTCAZ) [153]. (b) Hydrogen bond tape motif in the crystal structure of GUTCAZ, the side chain is shown as a small sphere for clarity.…”

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confidence: 99%

Crystal structures of amino acids: from bond lengths in glycine to metal complexes and high-pressure polymorphs

Görbitz

2015

Crystallography Reviews

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After the discovery of X-ray diffraction by crystals, amino acids were among the first organic compounds to have their solid-state structures investigated. The Cambridge Structural Database now contains more than 3500 entries for α-amino acids alone. After a short introduction dealing with the early history of X-ray structure determination, this review provides a classification of amino acid structures, describes essential structural elements, especially hydrogen bonding preferences and coordination to metal ions, and considers recent investigations on phase transitions as the result of extreme temperatures or pressure.

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“…Initially, the imines were limited to the highly active N-protected a-imino esters. [33][34][35] Later, it was extended to aryl aldimines. Several new methods have been developed recently, in which Cu(OTf) 2 /bisoxazoline complexes, 36 9-thiourea cinchona alkaloids, 37 chiral phosphoric acid, [38][39][40] and axially chiral cyclometalated bidentate N-heterocyclic carbene palladium(II) complexes 41 have been used as the catalysts.…”

Section: Introductionmentioning

confidence: 99%

“…40 In addition, the removals of the N-protecting groups remain unsolved. [33][34][35][36][37][38][39][40][41] In this note, we present an InCl 3 -catalyzed aza-Friedel-Crafts reaction of indoles, including the 2-substituted indoles, with aldimines prepared from O-pivaloylated b-D-galactosylamine. The reaction proceeds in good to high yields with high diastereoselectivity.…”

Section: Introductionmentioning

confidence: 99%