Quantum mechanical calculations were employed to predict the ratio of four stereoisomeric products expected from two complex reactions involving the aldol reactions of cyclohexanone with benzaldehyde or with isobutyraldehyde catalyzed by (S)-proline. Experimental tests of these predictions provide an assessment of the state-of-the-art in quantum mechanical prediction of products of complex organic reactions in solution.
[reaction: see text] Here we describe the proline-catalyzed Michael addition of unmodified ketones to nitro olefins. This novel reaction provides gamma-nitro ketones in modest enantioselectivity yet excellent yields.
The differential associations that job satisfaction and organizational commitment have with job performance and turnover intentions were studied in a sample of bank tellers and hospital professionals. Results showed that organizational commitment was more strongly related than job satisfaction with turnover intentions for the tellers, but not for the professionals. Job satisfaction was related more strongly than organizational commitment with supervisory ratings of performance for both samples. The findings suggest that specific job attitudes are more closely associated with task-related out-comes such as performance ratings, whereas global organizational attitudes are more closely associated with organization-related outcomes like turnover intentions.
We have developed proline-catalyzed direct asymmetric three-component Mannich reactions of ketones, aldehydes, and amines. Several of the studied reactions provide beta-amino carbonyl compounds (Mannich products) in excellent enantio-, diastereo-, regio-, and chemoselectivities. The scope of each of the three components and the influence of the catalyst structure on the reaction are described. Reaction conditions have been optimized, and the mechanism and source of asymmetric induction are discussed. We further present application of our reaction to the highly enantioselective synthesis of 1,2-amino alcohols.
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