The discovery in 1959 of stable nitroxide‐based free radicals such as the prototypical 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO) led to their use as electron spin resonance (ESR) spin labels in chemistry, biomedicine, and materials science. These nitroxides are prepared by the oxidation of secondary amines that contain no hydrogen atoms on the alpha‐carbons. The unique redox properties of nitroxides enable their use as oxidants in organic synthesis. The varied preparation and uses of oxoammonium salts as stoichiometric oxidants for alcohols are one subject of this review. Oxoammonium ions as oxidants for alcohols have a number of advantages, for example, the method is heavy‐metal free and some of the reactions can be performed in water or aqueous mixtures. A few side reactions are associated with these oxidations. The most serious is the fast reaction of the oxoammonium ion with free amines The several ways these oxidation reactions can be carried out are discussed in detail. They are: Oxidations using stoichimetric quantities of preformed oxoammonium salts carried out in either acidic, neutral, or basic conditions; reactions in which stoichiometric quantities of oxoammonium salts are generated in situ by disproportionation of a nitroxide in the presence of a strong acid; nitroxide‐catalyzed oxidations using a secondary oxidant; efficient nitroxide‐catalyzed oxidations of primary alcohols to carboxylic acids; and oxidations of primary alcohols or hemiacetals that can lead to lactones.

4-Acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium perchlorate, 1, is a stable, nonhygroscopic oxoammonium salt that is easily prepared and can be used for the oxidation of alcohols to ketones or aldehydes in near quantitative yields. The reaction is colorimetric, does not require anhydrous conditions, does not involve heavy metals, and can be carried out conveniently. Furthermore, the oxidant can be easily regenerated. The oxidation is somewhat specific in that the relative reactivities of an allyl alcohol (geraniol), benzaldehyde, and 1-decanol are about 100:1:0.1. The reaction is catalyzed by silica gel.

The mechanism of the oxidation of primary and secondary alcohols by the oxoammonium cation derived from 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) has been investigated computationally at the B3LYP/6-31+G* level, along with free energies of solvation, using a reaction field model. In basic solution, the reaction involves formation of a complex between the alkoxide anion and the oxoammonium cation in a pre-oxidation equilibrium wherein methoxide leads to a much larger formation constant than isopropoxide. The differences in free energy of activation for the rate-determining hydrogen transfer within the pre-oxidation complexes were small; the differences in complex formation constants lead to a larger rate of reaction for the primary alcohol, as is observed experimentally. In acidic solution, rate-determining hydrogen atom transfer from the alcohol to the oxoammonium cation had a large unfavorable free energy change and would proceed more slowly than is observed. A more likely path involves a hydride transfer that would be more rapid with a secondary alcohol than primary, as is observed. Transition states for this process were located.

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A new method for the selective oxidation of alcohols using organic oxoammonium salta generated by acidpromoted disproportionation of nitroxides in solution has been developed. Major advantages are high yields, ease of product isolation, and a high degree of selectivity in the presence of other functional groups.

Order-and Psychologists-in the Court This is not like squeezing the grapefruit one more time for that last bit of juice. It is more like remembering that there is the other half still untouched.Last September this column made a foray into the courtroom, did a bit of reconnoitering with the help of psychologists who knew the terrain, promptly took cover again to study the field maps. With the help of our colleagues who had lived among the natives, we interpreted the language of the land of law, looked a bit at its culture, and found the setting if not unsettling at least awfully awesome.The subject seems to appeal to our readers, who continue to express interest, report experiences, and, all in all, remind us that forensic psychology is here to stay. We turn, then, to that other half of the questionnaire which was being pretested on a group of some 40 colleagues describing some 80 professional brushes with the law (with a range of from 1 to 10 cases, a mode between 1 and 2). And here are some of the things we find.Where Did You Go? Court. What Did You Do? Testijy. The author of the best seller will pardon us if we adapt his apt title. It captures so well the spirit of our situation. For apparently psychologists go to all kinds of courts to testify in all types of cases on all sorts of issues.The list of courts in which our respondents have appeared covers the legal waterfront: federal, state, district, circuit, county, municipal. There is the superior court, the state supreme court, and the more restful sounding supreme bench. There are probate courts, domestic relations courts, and juvenile courts. And, if one wants more exotic places where psychologists have been, there is the County Assizes of the Supreme Court of Canada as well as Queen's Bench Court.The actions involved, as one might suspect, are hardly all of a piece. We referred to some of the more grisly in the earlier column. We add here only that, no matter what the case may be, from traffic fine to felony, whichever side tries most to win it, psychologists may well be in it.In the returns, cases in criminal law outweigh

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We describe the synthesis of the lesser-known stoichiometric oxidation reagent 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxoammonium tetrafluoroborate (1, Bobbitt's salt), as well as of 4-acetamido-(2,2,6,6-tetramethyl-piperidin-1-yl)oxyl (2, AcNH-TEMPO). Several representative oxidation reactions are also presented to demonstrate the salt's oxidative capabilities. Bobbitt's salt has a range of applications, from the oxidation of various alcohols to their corresponding carbonyl derivatives to the oxidative cleavage of benzyl ethers, whereas 2 has been shown to serve as a catalytic or stoichiometric oxidant. The oxyl radical can be obtained in 85% yield over two steps on a 1-mole scale from commercially available 4-amino-2,2,6,6-tetramethylpiperidine (5), and is far more cost-effective to prepare in-house than purchase commercially. An additional step converts the oxyl radical into the oxoammonium salt (1, Bobbitt's salt) in 88% yield, with an overall yield of 75%. The synthesis of the salt takes ∼5 d to complete. Oxoammonium salts are metal-free, nontoxic and environmentally friendly oxidants. Preparation of 1 is also inherently 'green', as water can be used as the solvent and the use of environmentally unfriendly materials is minimal. Moreover, after it has been used, the spent oxidant can be recovered and used to regenerate 1, thereby making the process recyclable.