Tetrahedra Subject

Tor a treatise on this subject, sec Morrison Asymmetric Synthesis, 5 vols. [vol. 4 co-cditcd by Scott] Academic Press New York, 1983-1985. For books, see N6gr4di Stereoselective Synthesis VCH New York, 1986 Eliel Olsuka Asymmetric Reactions and Processes in Chemistry American Chemical Society Washington, 1982 Morrison Mosher Asymmetric Organic Reactions Prentice-Hall Englewood Cliffs, NJ, 1971, paperback reprint, American Chemical Society Washington, 1976 Izumi Tai, Ref. I. For reviews, see Ward Chem. Soc. Rev. 1990, 19, 1-19 Whitesell Chem. Rev. 1989, 89, 1581-1590 Fujita Nagao Adv. Heterocycl. Chem. 1989, 45, 1-36 Kochetkov Belikov Russ. Chem. Rev. 1987, 56, 1045-1067 Oppolzer Tetrahedron 1987, 43, 1969-2004 Seebach Imwinkelried Weber Mod. Synth. Methods 1986, 4, 125-259 ApSimon Collier Tetrahedron 1986, 42, 5157-5254 Mukaiyama Asami Top. Curr. Chem. 1985, 127, 133-167 Martens Top. Curr. Chem. 1984, 125, 165-246 Duhamel Duhamel Launay Plaqucvcnt Bull. Soc.Chim. Fr. 1984,11-421-11-430 Mosher Morrison Science 1983,221, 1013-1019 Schollkopf Top. Curr. Chem. 

Shorn) Malsumura Onomura Yamada Synthesis 1987, 1099 Ginzcl Steckhan Tetrahedron 1987, 43. 5797. Ross Finkelslein Rudd J. Org. Chem. 1972,37, 2387. See also Moeller Tarazi Marzabadi Tetrahedron Lett. 1989,30, 1213 Shono Malsumura Tsubata Org. Synth. VII, 307. For a table of compounds subjected to this reaction, sec Shono Electroorganic Chemistry as a New Tool in Organic Synthesis-. Springer New York, 1984. pp. 63-66. 

It has been established that under intense milling in a planetary mill in a nitrogen atmosphere, titanium hydride may decompose with formation of defected structure characterized by partly non-occupied tetrahedron voids in a face-centered cubic sublattice of titanium atoms. This effect is accompanied by decrease in the crystal lattice parameter of titanium hydride subjected to intense milling for 60 min. 

Hexamethylenetetramine has been extensively studied in this respect30 , and it has been shown that for temperatures ranging above room temperature, reorientational motions are responsible for the strong relaxation. More exactly, hindered rotations interchange the tetrahedron apexes and the nuclei are thus subjected to a sudden reorientation of the electric field gradient. The correlation time of such motions can be derived from the observed signals and experimental results may be depicted by the relation... 

For previous recent reviews of this subject see (a) S. M. Weinreb and R. R. Staib, Tetrahedron, 1982, 38, 3087 (b) D. L. Roger and S. M. Weinreb, Hetero Diels-Alder Methodology in Organic Synthesis , Academic Press, Orlando, 1987 (c) T. Kametani and S. Hibino, Adv. Heterocycl. Chem., 1987, 42, 245 (d) J. Hamer (ed.), 1,4-Cycloaddition Reactions, the Diels-Alder Reaction in Heterocyclic Synthesis , Academic Press, New York, 1967. 

SiHj- has also been the subject of a few recent papers. Wilhite and Spialter found that the trigonal-bipyramidal form is stable by 71 kJ moI with respect to SiHi + H" and the tetragonal-pyramidal form stable by 58 kJ mol". The reaction proceeds with H" approaching the face of a silane tetrahedron withEitcn. 36 kJ mol". A barrier of 12 kJ mol" to the Berry pseudorotation was found. 

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