A facile one-pot preparation of potassium hydroxyaryl- and (hydroxyalkyl)aryltrifluoroborates

Potassium hydroxyaryl- and (hydroxyalkyl)aryltrifluoroborates have been prepared in a simple one-pot process from the corresponding hydroxy-substituted aryl halides in 51-98% yields through an in situ protection of the free hydroxyl group with t-BuLi. Also, we successfully performed a microwave-promoted Suzuki-Miyaura cross-coupling reaction of these substrates with aryl- and alkenyl bromides in the presence of 0.5 mol % of Pd(OAc)2 catalyst without ligands.     

Selective Methylation of Arenes: A Radical C−H Functionalization/Cross‐Coupling Sequence

A selective, nonchelation‐assisted methylation of arenes has been developed. The overall transformation, which combines a C?H functionalization reaction with a nickel‐catalyzed cross‐coupling, offers rapid access to methylated arenes with high para selectivity. The reaction is amenable to late‐stage methylation of small‐molecule pharmaceuticals.     

Sublimable bis(β-iminoenolate)palladium(II) complexes and their application as catalysts in Suzuki-Miyaura reactions

The Pd(II) complexes strongly chelated by two β-iminoenolate ligands were easily synthesized in only two steps, and purified based on their sublimable and highly stable property. The Pd(II) complexes anchored on a silica surface showed good catalytic activity in Suzuki-Miyaura reactions (up to 99% yield with 0.05?mol% catalyst). They tolerated a wide range of temperature (rt～110?°C) and various solvents, and could be reused multiple times after simple recovering process.     

Transmission reflection anomaly in second-harmonic generation from a monolayer

We show experimentally that in second-harmonic generation from a monolayer the radiation propagating in transmission and that in reflection can have very different magnitudes. The origin of this difference lies in destructive and constructive interference of the components of the nonlinear polarization that drive the field at the second-harmonic frequency.     

Small-molecule dimerization inhibitors of wild-type and mutant HIV protease: a focused library approach

We demonstrate that a focused library based on truncated, cross-linked interfacial peptides of HIV-1 protease produces effective dimerization inhibitors of the enzyme. By combining individual changes of the library into a single compound, we obtained a significantly more potent agent and found that an additive increase in inhibitor efficacy was obtained. The good activity of library members against an active-site drug-resistant protease mutant bodes well for dimerization inhibition as a complementary method to targeting the active site.     

Terpolymer Azeotropy

Data supporting the theory and conjectured existence of terpolymer azeotropes are examined. It is shown that the theory is based on questionable assumptions. It is also shown that the use of r₃₂ = r₃₁ = 0, for example, leads to fatal flaws in the prediction of terpolymer azeotropes. Furthermore, specific reactivity ratios used In predicting terpolymer azeotropes are questioned.     

Terpolymer Relationships and Azeotropes

In a 1983 paper in this Journal (A19, 693), Ham questioned the existence of ternary azeotropes. A recent paper by Quella [Makromol. Chem., 190, 1445 (1989)J has criticized the earlier thesis, in part on the basis that Ham's “indications have certainly not encouraged the search for ternary azeotropes,” and on the basis of “further experimental results from other authors”. This paper responds to Quella, further develops evidence against ternary azeotropes, and, in addition, discusses pertinent terpolymer interactions in terms of terpolymerization probabilities and in terms of general monomer reactivities.     

Digitalized Mirror Array and Its Application in Large Telescope: Principle and Case Studies

In this article, we report the principle and conceptual design of a fundamentally different technology in fabricating high precision aberrationfree optical devices. The tip-tilt of facet in a mirror array is produced bydigitally controlled line-tilts of rows and columns. It has not only provided a cost-effective designing methodology in optical physics but also led to a much finer precision of 1 mili arc sec or less. As examples of the application of the proposed digitalised optics, two case studies have been given: a 10 m Schmidt telescope (off-axis) and an 8 m Cassegrain telescope (on-axis).