Either amprenavir (1) or its C(2) diastereomer can be synthesized in a simple way by the use of a nitroaldol reaction carried out in the presence of one or the other of the two ammonium ions 2. The 1,3‐diamino‐2‐hydroxypropyl structural element of 1 is also found in many other peptidomimetics and HIV protease inhibitors. Described here is a new strategy for possible application to direct and stereocontrolled synthesis of such compounds.

[formula: see text] Highly enantioselective (up to 130:1) epoxidation of a variety of alpha,beta-enones to form alpha,beta-epoxy ketones is described along with a rational analysis of the mechanistic basis for this strong absolute stereochemical control by the chiral catalyst 2.

[formula: see text] The use of the chiral quaternary ammonium salts 1a and 1b makes possible enantioselective Michael reactions which have been applied to the asymmetric syntheses of (S)-ornithine (2) and the chiral 2-cyclohexenone 6.

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[reaction:see text] Enantioselective Michael addition of nitromethane to an alpha, beta-enone is a key step in the synthesis of (R)-baclofen.

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Water seepage in concrete threatens the safety of marine constructions and reduces the durability of concrete structures. This note presents a smart aggregate-based monitoring method to monitor the travel time evolution of a harmonic stress wave during the water infiltrating process in concrete structures. An experimental investigation, in which two plain concrete columns were examined under different water infiltration cases, verified the validity of the proposed monitoring method. The test results show that the travel time of the harmonic stress wave is sensitive to the development of water seepage in concrete and decreases with increasing water seepage depth. The proposed active monitoring method provides an innovative approach to monitor water seepage in concrete structures.