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Treatment of 3-aminocyclohex-1-enes with mCPBA in the presence of trichloroacetic acid gives the corresponding 1,2-anti-2,3-syn-1-trichloroacetoxy-2-hydroxy-3-aminocyclohexane with high levels of diastereoselectivity (90% de). This is consistent with a mechanism of oxidation involving hydrogen-bonded delivery of the oxidant by the allylic ammonium ion formed in situ, followed by highly regioselective ring-opening of the intermediate epoxide by trichloroacetic acid. The effect of conformational constraints upon the oxidation reaction is also examined.

Studies were conducted to determine the relationship of the postmortem pH decline of hot-boned broiler breast muscle (Pectoralis major) to the increased toughness often associated with hot boning. A total of 68 broilers were New York dressed, and trials were conducted to compare breast halves either hot boned at 0, 15, 30, 60, 120, or 240 min postmortem with the other (control) half allowed to remain on the carcass for 24 hr prior to removal. The pH values were taken on each bird at time of kill, time of excision on the excised or hot-boned muscle, and after 24 hr on both halves. Following a 24-hr ice chill, each muscle half was cooked at 100 C for 20 min, allowed to cool, and muscle tenderness determined using an Instron equipped with an Allo-Kramer shear cell. Results indicated that as postmortem pH values decreased, muscle toughness decreased with increased holding time prior to excision. Decreases in muscle pH values tended to level off at 5.9 after 4 hr or before, as did shear values of about 4.5 to 5.5 kg force/g sample. Thus, it appears that without the application of an effective accessory tenderizing treatment, muscle should be held for at least 4 hr postmortem prior to hot boning to avoid the adverse toughening effects commonly associated with hot-boned broiler breast meat.(Key words: hot boning, tenderness of hot-boned breast meat, muscle pH)

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A range of substituted aryl epoxides undergo efficient ring-opening hydrofluorination upon treatment with 0.33 equiv of BF(3) x OEt(2) in CH(2)Cl(2) at -20 degrees C to give the corresponding syn-fluorohydrins, consistent with a mechanism involving a stereoselective S(N)1-type epoxide ring-opening process. The benzylic fluoride products of these reactions are valuable templates for further elaboration, as demonstrated by the preparation of a range of aryl-substituted beta-fluoroamphetamines.

The stereochemical outcome observed upon alkylation of enolates derived from N-1-(1'-naphthyl)ethyl-O-tert-butylhydroxamates (chiral Weinreb amide equivalents) may be rationalized by a chiral relay mechanism. Deprotonation with KHMDS leads to a nonchelated (Z)-enolate in which the oxygen atoms adopt an anti-periplanar conformation. The configuration of the N-1-(1'-naphthyl)ethyl group dictates the conformation of the O-tert-butyl group and the configuration adopted by the adjacent pyramidal nitrogen atom. Highly diastereoselective enolate alkylation then proceeds anti to both the bulky tert-butyl group (sterically driven) and the N-lone pair (stereoelectronically driven).