Reversal of a Michael AdditionReaction.-The Michael addition of nucleophiles of type (II) and (IV) to the furanoside (I) proceeds in a highly stereoselective manner but with different stereochemical outcome compared to the Michael addition of aerofoil-shaped nucleophiles such as (VI) and (VIII). This unexpected reversal of relative asymmetric induction is ascribed to the effect exerted by the wing tip carbonyls of (VI) and (VIII). This effect is termed as stealth stereocontrol. -(BARRETT, A. G. M.; WEIPERT, P. D.; DHANAK, D.; HUSA, R. K.; LEBOLD, S. A.; J. Am. Chem. Soc. 113 (1991) 26, 9820-9824; Dep. Chem., Colo. State Univ., Fort Collins, CO 80523, USA; EN)
Synthesis of Silicon-Functionalized Dimethylsilyl Enol Ethers fromKetones.-The symmetrical dimethylsilyl bisenol ethers (III) are obtained by reaction of the ketones (I) with dichloromethylsilane (II) in the presence of triethylamine and sodium iodide. Reaction of ketones with N,N-diethylaminodimethylchlorosilane (V) in the presence of triethylamine and sodium iodide followed by various conversions provides a useful synthesis of silicon-functionalized dimethylsilyl enol ethers, e.g. (VI), (VIII), and the unsymmetrical dimethylsilyl bis-enol ethers (IX). -(RATHKE, M. W.; WEIPERT, P. D.; Synth. Commun. 21 (1991) 12-13, 1337-1351 Dep. Chem., Michigan State Univ., East Lansing, MI 48824, USA; EN)
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.