Intramolecular processes, with

The rearrangement of 24 to 19 is an intramolecular process with 1st order kinetics. The rearrangement does not occur by reductive elimination of TMS from 24 and by readdition of free TMS to the [(dtbpm)Pt(O)] fragment in a subsequent C-Si activation step. This possibility can be excluded rigorously by performing the 24 to 19 transformation in fully deuterated Si(CD3)4 or in hexamethydisi-loxane as solvents 24 only yields undeuterated 19 in d -TMS and does not lead to 21 in hexamethyl-disiloxane (which would have to be seen as a dissociative mechanism, as [(dtbpm)Pt(O)] had been previously shown to activate hexamethydisiloxane under the same reaction conditions). 

Intramolecular process with rhodium catalyst has been described for the syntheses of indane, dihydroindoles, dihydrofurans, tetralins, and other polycyclic compounds. Wilkinson catalyst is efficient for the cyclization of aromatic ketimines and aldimines containing alkenyl groups tethered to the K z-position of the imine-directing group. 

Syntheses of this class of compounds usually involve 1,2,5-thiadiazepine ring 333 (Figure 6) which is stable in the S-oxidized form and structurally represents cyclic pyrrole N-sulfonyl derivatives. Most of the synthetic strategies include formation of an S-Npyrroie bond in the early stages. A final cyclization step typically includes (i) intramolecular cyclization by creation of an N-X bond from a suitable pyrrole precursor or (ii) a 6 + 1 type cyclization that involves dielectrophilic species to form linker X and utilizes the nucleophilicity of the phenyl amino group and of the pyrrole ring at C2. Intramolecular processes with the formation... 

A rhodium-catalyzed route to bicyclic aziridines 561 from A -tosyloxycarbamates has been reported (Scheme 137) <2005JA14198>. Several olefins were tested in this intramolecular process with yields ranging between 62% and 79%. 

Contrary to earlier work, Caldwell et al. conclude from a detailed study of the 4,4-dimethylcyclohex-2-enone-l,l-diphenylethene system, that the (2n + 2n) photocycloaddition arises from a triplet exciplex, and Crimmins et al. report that the enone (15) undergoes highly diastereoselective intramolecular photoaddition to give (16) which is a key intermediate in a new route to spiro[5.4]decanes. Similar intramolecular processes with other enones, followed by treatment with tributyltin hydride and AIBN, provide a convenient route to bicyclic compounds such as (17) in good yield (Crimmins et al.), and irradiation of the optically active silylallene (18) gives (19) with an ee in excess of 99% (Shepard and Carreira). 

Although there is some variation among systems, the general order is5>6>3>7> 4 > 8 to 10-membered transition states. In more concentrated solutions intermolecular reactions may be competitive with four-membered ring formation. In summary, any intramolecular process with a 5-, 6-, 3-, or 7-membered transition state is aimost aiways faster than the corresponding intermoiecuiar process. 

The CO2 radicals react with disulfide groups in hCp at diffusion controlled rates to produce the RSSR radicals monitored at 410 nm (where RSSR radicals exhibit an absorption maximum) while no direct reduction of TlCu was observed (72). Instead, the electrons were further transferred to a Tl(Cu ) center in an intramolecular process with a rate constant of 28 2s at 279 K. An mframolecular electron equilibration with the T2/T3 center was then observed with a rate constant of 2.9 0.6 s determined independently at both 610 nm (TlCu absorption maximum) and at 330 nm, where the oxidation state of the trinuclear center can be monitored independently [Fig. 11 (a and fc)]. The internal ET process... 

At the moment, this has to be done as an intramolecular process with the help of another functional group. The two most popular methods, by Barton and by Kalvoda/HSusler, have been discussed in the Chapter 1 already, and here we present an application of the second one in the terpene series. 

In polymers, the Type II reaction may also involve an intramolecular process with a longer chain segment. 

The polyenyl peroxy radical (3.65) may undergo an intramolecular process with the formation of cyclic peroxides (5.66) [1538] ... 

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