David Crich Title Schaap Professor of Organic Chemistry Division Organic Education B.Sc., University of Surrey, UK (1981) D es Sciences, Université de Paris XI, France (1984, with DHR Barton) Postdoctoral, Institut de Chimie des Substances Naturelles, Gif-sur-Yvette, France (1984-1985, with DHR Barton and P Potier ) Office Chem 153 Phone (313)577-1915 E-Mail

In the Crich laboratory we are interested in the development of new synthetic methodology for the solution of problems in the synthesis of bioactive and other molecules. We have worked in numerous areas including radicals, radical cations, and asymmetric synthesis as suggested by the following recent review articles.

1. Generation of Alkene Radical Cations by Heterolysis of β-Substituted Radicals: Mechanism, Stereochemistry, and Applications in Synthesis, Crich, D.; Brebion, F.; Suk, D.-H. Topics in Current Chemistry, 2006, 263, 1-38.
   
   

2. Homolytic Substitution at the Sulfur Atom as a Tool for Organic Synthesis, Crich, D. Helv. Chim. Acta, 2006, 89, 2167-2182.
   
   

3. Chemistry of the Hexahydropyrrolo[2,3-b]indoles: Configuration, Conformation, Reactivity, and Applications in Synthesis, Crich, D.; Banerjee, A. Acc. Chem. Res. 2007, 40, 151-161.
   
   

4. Catalysis of Stannane-Mediated Radical Chain Reactions by Benzeneselenol, Crich, D.; Grant, D.; Krishnamurthy, V.; Patel, M. Acc. Chem. Res. 2007, 40, 453-463.

Much of our recent and ongoing work, however, is in the challenging field of stereoselective oligosaccharide synthesis, particularly the β-mannosides, rhamnosides, and their homologs, as well as of the α-sialosides. In the course of the last several years we have completed syntheses of numerous oligosaccharides containing the β-mannoside linkage, as well as several β-rhamnoside based oligosaccharides, and a synthesis of a bacterial polysaccharide centered around the very unusual β-D-glycero-D-mannoheptopyranoside. Several of these structures are represented below.

We also have a strong interest in the development of new methods for ligation, preferably under aqueous conditions. To this end we have developed a method for functionalization of cysteine in peptides that employs a dechalcogenative rearrangement of allylic disulfides as illustrated below. A current focus of our effort is in the development of methods for glycopeptide synthesis using this and related reactions.

In the Crich laboratory we believe that a sound understanding of mechanism provides a firm basis for the design of new synthetic methodology as is clear from a selection of our papers in the area of glycosidation mechanisms.

1. Are Glycosyl Triflates Intermediates in the Sulfoxide Glycosylation Method? A Chemical and ¹H, ¹³C, and ¹⁹F-NMR Spectroscopic Investigation, Crich, D.; Sun, S. J. Am. Chem. Soc. 1997, 119, 11217-11223.
   
   

2. Mechanism of 4,6-O-Benzylidene Directed β-Mannosylation as Determined by α-Deuterium Kinetic Isotope Effects, Crich, D.; Chandrasekera, N. S. Angew Chem. Int. Ed. 2004, 43, 5386-5389.
   
   

3. 4,6-O-Benzylidene-Directed β-Mannopyranosylation and α-Glucopyranosylation: the 2-Deoxy-2-fluoro- and 3-Deoxy-3-fluoro- Series of Donors and the Importance of the O2-C2-C3-O3 Interaction, Crich, D.; Li, L. J. Org. Chem. 2007, 72, 1681-1690.
   
   

4. Stereocontrolled Glycoside and Glycosyl Ester Synthesis. Neighboring Group Participation and Hydrogenolysis of 3-(2'-Benzyloxyphenyl)-3,3-dimethylpropanoates, Crich, D.; Cai, F. Org. Lett. 2007, 9, 1613-1615.