Coupling Catalytic Alkene Hydroacylation and α‑Arylation: Enantioselective Synthesis of Heterocyclic Ketones with α‑Chiral Quaternary Stereocenters

We report a strategy that combines alkene hydroacylation and enantioselective α-(hetero)­arylation reactions to form a wide variety of nitrogen-containing heterocyclic ketones bearing α-chiral quaternary stereogenic centers. Exo-selective, intramolecular Ni-catalyzed hydroacylations of <i>N</i>-homoallylindole- and <i>N</i>-homoallylpyrrole-2-carboxaldehydes form α-substituted six-membered heterocyclic ketones in up to 95% yield, while N-heterocyclic carbene (NHC) catalyzed hydroacylations of <i>N</i>-allylindole- and <i>N</i>-allylpyrrole-2-carboxaldehydes form α-substituted five-membered heterocyclic ketones in up to 99% yield. The racemic five- and six-membered products of Ni- and NHC-catalyzed hydroacylation reactions are readily transformed into heterocyclic ketones containing an α-chiral quaternary stereogenic center by enantioselective Ni-catalyzed α-arylation and α-heteroarylation reactions. The chiral, nonracemic products formed through a combination of alkene hydroacylation and α-(hetero)­arylation reactions are formed in moderate to high yields (44–99%) with excellent enantioselectivities (typically >95% ee). The identity of the precatalyst for Ni-catalyzed α-(hetero)­arylation is dictated by the identity of the α-substituted heterocyclic ketone starting material. α-(Hetero)­arylations of six-membered heterocyclic ketones occur at 65–85 °C in the presence of a catalyst generated in situ from Ni­(COD)₂ and (<i>R</i>)-BINAP or (<i>R</i>)-DIFLUORPHOS. α-(Hetero)­arylation of five-membered heterocyclic ketones must be conducted at room temperature in the presence of an [((<i>R</i>)-BINAP)­Ni­(η²-NC-Ph)] precatalyst or a catalyst generated in situ from Ni­(COD)₂, (<i>R</i>)-DIFLUORPHOS, and benzonitrile

RBF1 and dCAP-D3 regulate many of the same transcripts in the fly.

<p>RNA was isolated from <i>rbf1</i> mutant and <i>dCap-D3</i> mutant female third instar larvae and adult flies. cDNA was hybridized to Nimblegen 385 k whole genome arrays. A) Venn diagrams show the numbers of RBF1, dCAP-D3 or RBF1/dCAP-D3 shared target genes which exhibited at least a 2 fold log change in expression with a p value of ≤0.15. Genes significantly upregulated in the mutant flies are shown in red while genes significantly downregulated are shown in green. B) P values for shared RBF1 and dCAP-D3 target genes indicate that RBF1 and dCAP-D3 regulate a significant number of the same genes in both adults and larvae. The numbers above the diagonal represent p-values for upregulated shared subsets and are colored red while the numbers below the diagonal represent p-values for downregulated shared genes and are colored green. C) qRT-PCR analyses of 12 E2F targets shows that the majority of RBF1/dCAP-D3 shared targets are not E2F targets. The one target that was significantly upregulated in dCAP-D3 and RBF1 mutant flies, <i>CG5250</i>, is highlighted in red. Results are the average of three independent experiments involving 10 female flies per genotype. D) Significant (p≤0.05) Gene Ontology (GO) groupings for shared target genes include defense response genes in the adult fly. The top box lists GO categories for upregulated shared genes in mutant larvae only, and the bottom box lists selected GO categories for downregulated shared genes in adults only. There were no significant GO groupings for upregulated shared target genes in adults or for downregulated shared target genes in the larvae.</p

RBF1 and dCAP-D3 are necessary for the ability to clear bacteria <i>in vivo</i>.

<p>Adult female flies expressing RBF1 (purple) or dCAP-D3 (red) dsRNAs under the control of <i>yolk-GAL4</i> were infected with the Gram positive bacterium, <i>Staphylococcus aureus</i>. Flies expressing GFP dsRNAs under the control of <i>yolk-GAL4</i> (green) were used as “wild-type” controls. Eater mutants which are defective in phagocytosis (blue) or flies expressing IMD dsRNAs which are compromised in a major innate immune signaling pathway (yellow) were used as positive controls. Results demonstrate that at 15 hours following infection, flies expressing reduced levels of dCAP-D3 or RBF1 in the fat body cells exhibit increased numbers of bacteria in comparison to wild type controls. Three independent experiments are shown and results for each experiment are the average of three sets of three infected adults, per genotype, per timepoint. Asterisks emphasize statistical significance (p≤0.05) as determined by a students paired t-test.</p

Complete AMP induction following bacterial infection depends on dCAP-D3 and RBF1.

<p>Adult female flies expressing RBF1 (purple) or dCAP-D3 (red) dsRNAs under the control of <i>yolk-GAL4</i> were infected with the Gram positive bacteria, <i>Staphylococcus aureus</i>. A) qRT-PCR analyses for transcript levels of the <i>Drosomycin</i> AMP gene in these flies show that while flies expressing GFP dsRNAs under the control of <i>yolk-GAL4</i> (green) undergo a large induction of AMPs at 8–24 hours post-infection, flies expressing dCAP-D3 or RBF1 dsRNA in the fat body fail to exhibit maximal, sustained induction. B) qRT-PCR analyses for transcript levels of the <i>Diptericin</i> AMP gene in these flies show that while flies expressing GFP or RBF1 dsRNAs under the control of <i>yolk-GAL4</i> (green) undergo a large induction of AMPs at 8–24 hours post-infection, flies expressing dCAP-D3 dsRNA in the fat body fail to exhibit maximal, sustained induction. The inset boxes in the upper right corner of each graph are a larger representation of the 0 hour timepoint and depict basal transcription levels. Asterisks emphasize statistical significance (p≤0.05) as determined by a students paired t-test. Three independent experiments are shown and results for each experiment are the average of three sets of five infected adults per genotype, per timepoint.</p

dCAP-D3 is necessary for a proper immune response to bacterial infection.

<p>Adult female flies expressing dCAP-D3 (red) dsRNAs under the control of <i>yolk-GAL4</i> were infected with the Gram positive bacterium, <i>Staphylococcus aureus</i> (A) or the Gram negative bacterium, <i>Pseudomonas aeruginosa</i> (B). Flies expressing GFP dsRNAs under the control of <i>yolk-GAL4</i> (green) were used as “wild-type” controls. Eater mutants which are defective in phagocytosis (blue) or flies expressing IMD dsRNAs which are compromised in a major innate immune signaling pathway (yellow) were used as positive controls. Results demonstrate that flies expressing reduced levels of dCAP-D3 in the fat body cells are more susceptible to either type of infection than wild type controls. Three independent experiments are depicted with results of each experiment shown as the average of three sets of 10 infected adults per genotype. These experiments were also performed using a sterile needle dipped in PBS to rule out death as a result of wounding and survival curves matched those of yolk-GAL4 expressing flies (data not shown). Results are presented as cox regression models with statistical significance (p≤0.05) represented as shaded areas above and below the curves.</p

Basal AMP transcript levels are activated by RBF1 and dCAP-D3 specifically in the fat body.

<p>A) Immunofluorescence analysis of RBF1 and dCAP-D3 performed on cryosections of adult female flies expressing GFP under the control of the fat body specific <i>yolk-GAL4</i> driver indicates that RBF1 and dCAP-D3 co-localize in the nuclei of fat body cells. Yellow arrows highlight fat body cells. B) qRT-PCR analysis of cDNA from 1) flies expressing driver alone (<i>yolk-GAL4/+;+;+</i>), 2) flies expressing <i>rbf1 dsRNA (yolk-GAL4;+;UAS-rbf1 dsRNA)</i> in the fat body cells and 3) flies expressing <i>dCAP-D3 dsRNA (yolk-GAL4;+;UAS-dCAP-D3 dsRNA)</i> in the fat body cells shows significant decreases in AMP levels. For each genotype, N = 10.</p

An LQG approach to self-tuning control with application to robotics

Self-tuning control has been recognised as an effective approach for mechanical manipulator control design due to its ability to cope with the presence of nonlinearities and uncertainties in robot dynamic models. The vast majority of existing self-tuning controllers are based on a linear plant description, the fact that most industrial processes are nonlinear is taken into account by regarding the plant as a sequence of pseudolinear descriptions. Therefore, as the plant operating point changes, the nonlinear plant dynamics are reflected as time varying parameters in the linear plant description. The applicability of this approach has been demonstrated by Koivo and Guo [1] where manipulator joint angular position is the controlled variable. This work is extended in Koivo et al [2] to the case in which the manipulator is controlled directly in the cartesian coordinate system. It is found that convergence of the parameter estimates may not be achieved during the finite time over which the· motion takes place. Therefore this approach is particularly suited to repetitive tasks where the last estimates from the previous run can be used as the initial estimates. Lelic and Wellstead [3] have successfully applied generalised pole placement to the control of a 5 axis electrically actuated robot-manipulator