The title compound, C(24)H(37)BrO(3), is a tetra-cyclic diterpenoid with a beyerane skeleton, synthesized by esterification of isosteviol. It comprises a fused four-ring system A/B/C/D. Rings A and B have a chair conformation, whereas ring C is an unsymmetrical distorted chair; the remaining five-membered ring D adopts an envelope conformation. The stereochemistry of the A/B and B/C ring juncti...

An operationally simple one-pot, two-step procedure for the desymmetrization of benzils is herein described. This consists in the chemoselective cross-benzoin reaction of symmetrical benzils with aromatic aldehydes catalyzed by the methyl sulfinyl (dimsyl) anion, followed by microwave-assisted oxidation of the resulting benzoylated benzoins with nitrate, avoiding the costly isolation procedure....

Visible light photoredox/nickel dual catalysis has been employed in the cross-coupling of acyl chlorides with potassium alkyltrifluoroborates. This protocol, based on single-electron-mediated alkyl transfer, circumvents the restriction of using reactive alkylmetallic nucleophiles in transition-metal-catalyzed acylation and achieves a mild and efficient method for the synthesis of unsymmetrical ...

Cu(OAc)(2)-mediated dehydrogenative cross-coupling between two heteroarenes has been realized in the absence of any other additive. A mechanism involving a formal Cu(II) to Cu(0) route by convergent disproportionation of the copper mediator is proposed and has been evidenced by copper mirror formation during the reaction. This synthetic protocol provides a concise and "green" access to unsymmet...

Facile preparations of chiral [Ru(Cp*)]- and [Ru(Cp')]-based allyl complexes featuring N,O chelate derived from (+)-nopinone are described. Single crystal X-ray structural analysis of one complex revealed the preferential configuration of the ruthenium centre and the orientation of the unsymmetrical allylic substituent. Applications of these complexes in catalysis for nucleophilic allylic subst...

trans-Diepoxide 1 is well-known to react with aliphatic amines and the azide ion to give exclusively the 1,3-diol products. However, we observed that by judicious choice of conditions, reaction with anilines can give predominantly the 1,3-diol (3) or the heretofore rarely seen C(i)-symmetric 1,4-diol (4). Synthesis of an unsymmetrical 1,4-diol from two different anilines is also demonstrated. T...

Simple amine and diamine derivatives can promote the palladium catalysed direct β-C-H arylation of aliphatic aldehydes via transient imine formation. Trifluoroacetate was shown to be crucial in promoting the reaction. Sub-stoichiometric quantities of simple N-tosylethylenediamine was shown to form a bidentate directing group with an imine linkage. Isolation of an unsymmetrical palladacycle has ...

SP1 protein as a new type of biological nanopore is described and is utilized to distinguish single-stranded DNA at the single-molecule level. Using the SP1 nanopore to investigate single molecule detection broadens the existing research areas of pore-forming biomaterials from unsymmetrical biological nanopores to symmetrical biological nanopores. This novel nanopore could provide a good candid...

The Alamouti space-time code for transmission diversity is extended recursively to 2n×2n antenna elements as well as to unsymmetrical arrays of the size m × n. The proposed schemes exhibit two significant advantages: they allow for higher diversity (of degree 2 for the symmetrical case) and at the same time can be implemented as zero-forcing or MMSE type at low complexity avoiding any matrix in...

It is said that a forkball has a large drag force among various pitched balls in baseball games. To investigate this reason, the authors solve flows around a rotating baseball thrown in several conditions and visualized them. We found that the wake of the forkball is strongly influenced by the seam position and changes its direction like a knuckle ball because its spin is slow. The strong drag ...