A mild, general, and functional group tolerant intramolecular hydroalkoxylation and hydroacyloxylation of unactivated olefins using a Co(salen) complex, an N-fluoropyridinium salt, and a disiloxane reagent is described. This reaction was carried out at room temperature and afforded five- and six-membered oxygen heterocyclic compounds, such as cyclic ethers and lactones. The Co complex was optimized for previously rare medium ring formation by hydrofunctionalization of unactivated olefins. The powerful Co catalyst system also enables the deprotective hydroalkoxylation of O-protected alkenyl alcohol and hydroacyloxylation of alkenyl ester to afford cyclic ethers and lactones directly. The substrate scope and mechanistic proof of deprotection were investigated. The experimental evidence supports the concerted transition state of the bond-forming step involving a cationic Co complex.

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Hic-5 is a focal adhesion LIM protein serving as a scaffold in integrin signaling. The protein comprises four LD domains in its N-terminal half and four LIM domains in its C-terminal half with a nuclear export signal in LD3 and is shuttled between the cytoplasmic and nuclear compartments. In this study, immunoprecipitation and in vitro cross-linking experiments showed that Hic-5 homo-oligomerized through its most C-terminal LIM domain, LIM4. Strikingly, paxillin, the protein most homologous to Hic-5, did not show this capability. Gel filtration analysis also revealed that Hic-5 differs from paxillin in that it has multiple forms in the cellular environment, and Hic-5 but not paxillin was capable of hetero-oligomerization with a LIMonly protein, PINCH, another molecular scaffold at focal adhe- Protein-protein interaction provides the fundamental and structural molecular framework for biological systems, organizing a diverse array of cellular activities. According to genome-wide analyses, it is likely that biological networks make use of a restricted number of modular protein-binding domains, such as Src homology 2 (SH2) 2 , SH3, WD, PDZ, and the ankyrin repeat in a cassette-like fashion to generate complexity. In such biological systems, the so-called scaffolding protein, which possesses multiple modular protein-binding domains, is thought to play an essential role in integrating diverse cellular pathways. Like a hub, it mediates multiple protein-protein interactions simultaneously, thereby assembling multicomponent complexes as well as directing targets to discrete subcellular locations and modulating their activities. The LIM domain, whose designation is derived from the first letter of the founders LIN-11, Isl1, and MEC-3, is one of the modular protein-binding domains found in numerous eukaryotic proteins, consisting of a conserved cysteine/histidine-rich sequence coordinating two zinc ions that organize a double zinc finger structure essential for LIM domain function. As described in the extensive review by Kadrmas et al. (1), 135 LIM-encoding sequences are predicted to exist within as many as 58 genes in the human genome. In comparison, sequences for two other protein-binding domains, SH2 and -3, number 115 and 253, respectively. The LIM sequences are often connected with sequences encoding heterologous domains including the homeodomain, catalytic domains, and cytoskeletalbinding domains or other protein-binding modules, such as SH3, PDZ, and LD motifs. The combinations of LIM domains with a variety of these heterologous domains, characterizing individual families of LIM proteins, are the molecular basis for their roles in processes ranging from gene expression and cell adhesion to signal transduction. Among the LIM families, there are some consisting of LIM domains and other modular protein-binding domains and known to function as scaffolding proteins for cellular signaling.Hic (hydrogen peroxide-inducible clone)-5 is one such scaffolding LIM protein belonging to the paxillin family, consisting of four LD d...

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