Showing papers by "Keiji Maruoka published in 1989"
113 citations
78 citations
TL;DR: The Claisen rearrangement of bisallyl vinyl ethers with exceptionally bulky organoaluminum reagents exhibits unprecedented regiochemical control not observable in the ordinary thermal rearrangements.
29 citations
TL;DR: A review of the state-of-the-art of organoaluminum- or organoboron-mediated asymmetric reactions in natural product synthesis can be found in this article.
Abstract: This paper will review the current state-of-art of organoaluminum- or organoboron-mediated asymmetric reactions in the natural product synthesis. The newly developed methods heavily depend on the characteristic features of main group organometallic compounds. Asymmetric Diels-Alder reaction, pioneered by Walborsky (ref. l), has been established as one of the most important tools in modern synthesis of natural products. In the study of the influence of concave-convex topological features on asymmetric Diels-Alder reactions, a number of fascinating chiral auxiliary groups were reported (ref. 2). However, readily available dimen- thy1 fumarate appears to deserve careful reinvestigations since its primitive topological feature seems to be underestimated. Thus, the Lewis acid coordinated fumarate is considered to exist in the s-trans form predominantly and the two menthyl groups should cooperatively cover the re face of the molecule. A series of dienes was then subjected to Diels-Alder reaction with or- ganoaluminum reagent at low temperature and all the attempted reaction proceeded with excel- lent stereoselection (ref. 3).
8 citations
TL;DR: In this article, an overview of the development trends in highly discriminative reactions using novel Lewis acid catalysts is given with the aid of selected examples and a novel reactivity of acyloxyborane derivatives and their usefulness in organic synthesis is demonstrated.
Abstract: With the aid of selected examples an overview is given of the development trends in highly discriminative reactions using novel Lewis acid catalysts. 1) Bulky organoaluminum reagent, methylaluminum 3,3′-bis(triphenylsilyl)-1,1′-bi-2-naphthoxide, has been successfully utilized for enantioselective activation of carbonyl moiety. 2) A novel reactivity of acyloxyborane derivatives and their usefulness in organic synthesis is demonstrated. As an example, asymmetric Diels-Alder reaction catalyzed by new acyloxyboranes derived from chiral acids is described.
3 citations
TL;DR: The influence of electronic and steric effects of modified organoaluminum reagents to the stereoselectivity in the Diels-Alder and hetero-Diels Alder reactions has been examined in this article.
Abstract: The influence of electronic and steric effects of modified organoaluminum reagents to the stereoselectivity in the Diels-Alder and hetero-Diels-Alder reactions has been examined.