Soluble Cu(1) and Cu(I1) triflate and perchlorate salts are efficient catalysts for the aziridination of olefins employing (N-@-tolylsulfonyl)imino)phenyliodinane, PhI=NTs, as the nitrene precursor. Electron-rich as well as electron-deficient olefins undergo aziridination with this reagent in 55-958 yields, at temperatures ranging from -20 OC to +25 OC. The catalyzed nitrogen atom-transfer reaction to enol silanes and silylketene acetals has also been developed to provide facile syntheses of a-amino ketones. Other metal complexes were found to be less effective at catalyzing the reaction, while PhI=NTs proved to be superior to other imido group donors as the nitrene precursor. Reaction rates and yields are enhanced in polar aprotic solvents such as MeCN and MeN02. Reaction stereospecificity in the aziridination of cis and trans disubstituted olefins was evaluated and found to be both catalyst and substrate dependent. Intermolecular competition experiments between pairs of mono-and disubstituted olefins indicate that the olefin selectivity profile for the reaction is independent of the oxidation state of the copper catalyst employed. It is concluded that these reactions are proceeding through the 2+ catalyst oxidation state under the conditions employed in this study.

This review provides a personal account of the explorations of a research group in oligosaccharide and glycoconjugate construction. The journey began twenty years ago with the study of Diels–Alder reactions of complex dienes. By extending this methodology to aldehydo‐type heterodienophile equivalents, access to unnatural glycals was gained (LACDAC reaction). From this point a broad‐ranging investigation of the use of glycals in the synthesis of oligosaccharides and other glycoconjugates was begun. Mobilization of glycals both as glycosyl donors and glycosyl acceptors led to the strategy of glycal assembly. Several new glycosylation techniques were developed to provide practical underpinning for this logic of glycal assembly. Glycal‐based paradigms have been shown to be nicely adaptable to solid phase supported synthesis. Moreover, glycal assembly—both in solution and on solid phases—has been used to gain relatively concise and efficient entry to a variety of biologically interesting and potentially valuable constructs. Some of these syntheses, particularly in the field of tumor antigens, have led to novel compounds which are in the final stages of preclinical assessment. This review presents an account of the chemical reasoning at the center of the program.

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Over the last decade, the stereochemical attributes of the aldol reaction have been improved through the introduction of architecturally refined enolate metal centers.1 The most efficient of these processes utilizes boron enolates (la, eq 1), which provide a well-ordered transition state leading to predictably high levels of stereoselection. In continuing studies in this area, we have discovered that tetrachlorotitanium enolates (lb, eq 1), generated directly from the corresponding ketone or carboxylic acid derivative (TiCl4, R3N, CH2C12, -78 or 0 °C),2•3 45participate in highly se-

This article describes recent advances in the development and biological evaluation of small molecule inhibitors for the serine/threonine kinase Akt (PKB). Akt plays a pivotal role in cell survival and proliferation through a number of downstream effectors. Recent studies indicate that unregulated activation of the PI3K/Akt pathway is a prominent feature of many human cancers and Akt is over-expressed or activated in all major cancers. Akt is considered an attractive target for chemotherapy and it has been postulated that inhibition of Akt alone or in combination with standard cancer chemotherapeutics will reduce the apoptotic threshold and preferentially kill cancer cells. The development of specific and potent inhibitors will allow this hypothesis to be tested in animals. The majority of small molecule inhibitors in this nascent field are classic ATP-competitive inhibitors which provide little specificity. Phosphatidylinositol (PI) analogs have been reported to inhibit Akt, but these inhibitors may also have specificity problems with respect to other PH domain containing proteins and may have poor bioavailability. None of the inhibitors in these classes have been reported to have Akt isozyme specificity. Recently, novel allosteric inhibitors have been reported which are pleckstrin homology domain dependent and exhibit Akt isozyme selectivity. Inhibitors in this class may have sufficient potency and specificity to test for tumor efficacy in animal models and recently reported preliminary experiments are reviewed.

This article describes recent advances in the development and biological evaluation of allosteric and ATP-competitive small molecule inhibitors for the serine/threonine kinase Akt (protein kinase B, PKB). Unregulated activation of the PI3K/Akt/PTEN pathway is a prominent feature of many human cancers and Akt is over-expressed or activated in all major cancers making Akt an exciting new target for cancer therapy. The development of Akt inhibitors has been complicated and hampered by the presence of three Akt isozymes, (Akt1, Akt2 and Akt3) which differ in function and tissue distribution, as well as a lack of Akt specific inhibitors. In the past 18 months, a large number of reports have appeared describing the discovery and development of allosteric Akt kinase inhibitors and classical ATP-competitive Akt kinase inhibitors. This review will discuss the PI3K/Akt/PTEN pathway, allosteric and ATP-competitive Akt kinase inhibitors, their biological evaluation and progress towards target validation.