Ring expansion of 5- to 6-member zirconacycles by carbenoid insertion
摘要:
A wide range of carbenoids (1-lithio-1-halo species), including those with alpha-SiR3, OEt, SPh, SO2Ph, P(O)(OEt)(2), and CN substituents, insert into 5-member zirconacycles (saturated and unsaturated, mono- and bi-cyclic) to afford functionalized 6-member zirconacycles. 1-Lithio-1-haloalkenes insert to afford 6-member zirconacycles with an alkylidene substituent next to the metal. Unexpected double insertion of some carbenoids, and evidence for endocylic beta-hydride transfer processes provide additional mechanistic interest. (C) 2003 Elsevier Ltd. All rights reserved.
Cycloisomerization of Acetylenic Vinyllithiums: Sequential Anionic Cyclization-Cycloaddition as a Route to Polycyclic Ring Systems
摘要:
Acetylenic vinyllithiums, generated by low-temperature metal-halogen exchange, were found to undergo facile 5-exo-dig cyclization to afford isomerically pure conjugated 1,3-bis-exocyclic dienes which serve as reactive precursors to complex polycyclic materials through subsequent Diels-Alder methodology.
Tandem Insertion of Halocarbenoids and Lithium Acetylides into Zirconacycles: A Novel Rearrangement to Zirconium Alkenylidenates by β-Addition to an Alkynyl Zirconocene
作者:Jozef Stec、Emma Thomas、Sally Dixon、Richard J. Whitby
DOI:10.1002/chem.201002962
日期:2011.4.18
Tandem insertion of 1,1‐dihalo‐1‐lithio species (halocarbenoids) and lithium alkynides into zirconacyclopentenes and zirconcyclopentanes affords carbocyclic products in high yields via an unusual rearrangement that probably involves addition of an organolithium species to the β‐position of a zirconium–alkyne complex to give an alkenylidene–zirconate species. A wide variety of cyclopentanoid organic
A Rearrangement to a Zirconium–Alkenylidene in the Insertion of Dihalocarbenoids and Acetylides into Zirconacycles
作者:Emma Thomas、Sally Dixon、Richard J Whitby
DOI:10.1002/anie.200602822
日期:2006.10.27
Small Molecule Agonists of the Orphan Nuclear Receptors Steroidogenic Factor-1 (SF-1, NR5A1) and Liver Receptor Homologue-1 (LRH-1, NR5A2)
作者:Richard J. Whitby、Jozef Stec、Raymond D. Blind、Sally Dixon、Lisa M. Leesnitzer、Lisa A. Orband-Miller、Shawn P. Williams、Timothy M. Willson、Robert Xu、William J. Zuercher、Fang Cai、Holly A. Ingraham
DOI:10.1021/jm1014296
日期:2011.4.14
The crystal structure of LRH-1 ligand binding domain bound to our previously reported agonist 3-(E-oct-4-en-4-y1)-1-phenylamino-2-phenyl-cis-bicyclo[3.3.0]oct-2-ene 5 is described. Two new classes of agonists in which the bridgehead anilino group from our first series was replaced with an alkoxy or 1-ethenyl group were designed, synthesized, and tested for activity in a peptide recruitment assay. Both new classes gave very active compounds, particularly against SF-1. Structure-activity studies led to excellent dual-LRH-1/SF-1 agonists (e.g., RJW100) as well as compounds selective for LRH-1 (RJW101) and SF-1 (RJW102 and RJW103). The series based on 1-ethenyl substitution was acid stable, overcoming a significant drawback of our original bridgehead anilino-substituted series. Initial studies on the regulation of gene expression in human cell lines showed excellent, reproducible activity at endogenous target genes.