Mechanistic proposals for the carbocation cascade reaction leading to the tricyclic sesquiterpene pentalenene are assessed in light of the results of isotopically sensitive branching experiments with the H309A mutant of pentalenene synthase. These experimental results support a mechanism for pentalenene formation involving a 7-protoilludyl cation whose intermediacy was first predicted using qua...

A new coupling-isomerization-Claisen domino reaction starting from electron deficient halides and 1-(hetero)aryl propargyl trityl ethers dichotomizes in the concluding steps of the sequence and gives rise to the formation of tricyclo[3.2.1.0(2,7)]oct-3-enes, enones, 1H-isochromenes, or indans as a consequence of minute differences of substituent effects.

Reduction of ribono-1,4-lactones and gulono-1,4-lactone as well as ribono-1,5-lactone and glucono-1,5-lactones with LTBH (1.2 equiv.) in CH2Cl2 at 0 °C for 30 min provided the corresponding pentose or hexose hemiacetals in high yields. Commonly used in carbohydrate chemistry protecting groups such as trityl, benzyl, silyl, acetals and to some extent acyls are compatible with this reduction.

An efficient synthesis of the angiotensin-II inhibitor valsartan (Diovan®) is presented. Directed ortho-metalation of 5-phenyl-1-trityl-1H-tetrazole (6) and its Negishi coupling with aryl bromide 5 are the key steps of the synthesis. This method overcomes many of the drawbacks associated with previously reported syntheses.

Stable configurations and Lamport clocks have garnered improbable interest from both cyberneticists and researchers in the last several years. In our research, we disconfirm the synthesis of thin clients, which embodies the important principles of networking. We construct new mobile theory (TRITYL), which we use to verify that compilers and operating systems are mostly incompatible.

Synthesis, photophysical properties and submicron ring formation of functionalized uracil morpholino monomers have been reported. A series of characterization techniques indicated that the rings are formed by the inter-molecular hydrogen bonding of the uracil nucleus having a trityl-protected morpholino moiety. This is the smallest nucleoside unit known to date for submicron size ring formation.

The stoichiometric reaction of trityl cation with two equivalents of Ph2PH affords the phosphine stabilized phosphenium salt [Ph2(H)PPPh2][B(C6F5)4] via hydride abstraction, while catalytic amounts of B(p-HC6F4)3 effects catalytic phosphine dehydrocoupling with the liberation of H2. This reaction is accelerated by the presence of olefin or imine, effecting concurrent hydrogenation.

The encapsulation of trityl-functionalised C60 molecules inside carbon nanotubes drastically affects the intermolecular interactions for this species. Whilst the orientations of molecules in the crystal are often controlled by thermodynamics, the molecular orientations in nanotubes are a result of kinetic control imposed by the mechanism of entry into and encapsulation within the nanotube.

Abietadiene synthase (AS) catalyzes the complex cyclization-rearrangement of (E,E,E)-geranylgeranyl diphosphate (8, GGPP) to a mixture of abietadiene (1a), double bond isomers 2a-4a and pimaradienes 5a-7a as a key step in the biosynthesis of the abietane resin acid constituents (1b-4b) of conifer oleoresin. The reaction proceeds at two active sites by way of the intermediate, copalyl diphosphat...

2-(Trimethylsilyl)ethyl 2,2,2-trichloroacetimidate is readily synthesized from 2-trimethylsilylethanol in high yield. This imidate an effective reagent for the formation of 2-trimethylsilylethyl esters without need exogenous promoter or catalyst, as carboxylic acid substrate acidic enough to promote ester additive. A deuterium labeling study indicated that a ?-silyl carbocation intermediate inv...