Stephen C. Bergmeier

Bio: Stephen C. Bergmeier is an academic researcher from Ohio State University. The author has contributed to research in topics: Aziridine & Bicyclic molecule. The author has an hindex of 12, co-authored 27 publications receiving 1316 citations.

Acylnitrene Route to Vicinal Amino Alcohols. Application to the Synthesis of (-)-Bestatin and Analogues.

Abstract: Bestatin, valinoctin A, and microginin are naturally occurring small peptides containing a nonproteinogenic alpha-hydroxy-beta-amino acid at the N-terminus of the peptide chain. We report here our development of a general method for the synthesis of alpha-hydroxy-beta-amino acids and exemplify this with a synthesis of (-)-bestatin and analogues. Our synthesis utilizes an intramolecular acylnitrene-mediated aziridination to generate a key bicyclic aziridine in excellent yield and stereoselectivity. This bicyclic aziridine can be opened with a number of organometallic reagents to provide a series of substituted oxazolidinones. The oxazolidinones are readily converted to bestatin and a series of bestatin analogues. As part of this approach, we have developed a new method for the synthesis of azidoformates. We have also demonstrated that oxazolidinones can be selectively hydrolyzed in the presence of peptide bonds. This acylnitrene route to bestatin should prove useful for the synthesis of a variety of analogues of bestatin as well as other alpha-hydroxy-beta-amino acids and their corresponding peptides.

Synthesis of Vicinal Amino Alcohols via a Tandem Acylnitrene Aziridination-Aziridine Ring Opening.

Abstract: A facile synthesis of differently substituted vicinal amino alcohols is reported. We have demonstrated that these amino alcohols could be readily prepared from the oxazolidinones by treatment with aqueous base. We have synthesized a variety of substituted bicyclic aziridine precursors from the corresponding azidoformates using an intramolecular aziridination reaction. The nucleophilic ring opening of these bicyclic aziridines using carbon, oxygen, nitrogen, sulfur, and halogen-containing nucleophiles provided the oxazolidinones in good yield with high regioselectivity. In all cases, nucleophilic attack occurred exclusively at the least substituted carbon of the aziridine ring. Consequently, our approach allows for convenient and rapid access to the vicinal amino alcohol functionality, an important structural component of many natural products.

Organic Azides: An Exploding Diversity of a Unique Class of Compounds

Abstract: Since the discovery of organic azides by Peter Griess more than 140 years ago, numerous syntheses of these energy-rich molecules have been developed. In more recent times in particular, completely new perspectives have been developed for their use in peptide chemistry, combinatorial chemistry, and heterocyclic synthesis. Organic azides have assumed an important position at the interface between chemistry, biology, medicine, and materials science. In this Review, the fundamental characteristics of azide chemistry and current developments are presented. The focus will be placed on cycloadditions (Huisgen reaction), aza ylide chemistry, and the synthesis of heterocycles. Further reactions such as the aza-Wittig reaction, the Sundberg rearrangement, the Staudinger ligation, the Boyer and Boyer-Aube rearrangements, the Curtius rearrangement, the Schmidt rearrangement, and the Hemetsberger rearrangement bear witness to the versatility of modern azide chemistry.

Mitsunobu and Related Reactions: Advances and Applications

Abstract: 10. Patented Literature 2616 10.1. Esterification 2616 10.2. Ether Formation 2619 10.2.1. Etherification without Cyclization 2619 10.2.2. Etherification with Cyclization 2624 10.3. N-Alkylation 2625 10.4. Other Reactions 2627 11. Summary and Outlook 2628 12. Note Added in Proof 2628 13. Abbreviations Used in This Review 2629 14. Acknowledgments 2629 15. Supporting Information Available 2630 16. References 2630