Scheffer studies

Scheffer and his colleagues13-15 31 71-74 have studied a wide range of systems in which the first component was ethane, ethylene, or... 

J. Scheffer (ed.) Organic Chemistry in Anisotropic Media (Tetrahedron Symposia-in-Print, Number 29), Tetrahedron 43,1197 (1987) Desiraju, G. R. (ed.) Organic Solid State Chemistry (Studies in Organic Chemistry, Vol. 32), Amsterdam—New York, Elsevier 1987... 

The publication (70) in 1976 of the preparation of optically active epoxyketones via asymmetric catalysis marked the start of an increasingly popular field of study. When chalcones were treated with 30% hydrogen peroxide under (basic) phase-transfer conditions and the benzylammonium salt of quinine was used as the phase-transfer catalyst, the epoxyketones were produced with e.e. s up to 55%. Up to that time no optically active chalcone epoxides were known, while the importance of epoxides (arene oxides) in metabolic processes had just been discovered (71). The nonasymmetric reaction itself, known as the Weitz-Scheffer reaction under homogeneous conditions, has been reviewed by Berti (70). 

B. Scheffer, I.I. Heijeinga, and J.A. MouUjn, An electron spectroscopy and X-ray diffraction study of nickel oxide/alumina and nickel oxide/tungsten trioxide/alumina catalysts, J. Phys. Chem. 91, 4752 759 (1987). 

Natarajan A, Wang K, Ramamurthy V, Scheffer JR, Patrick B (2002) Org Lett 4 1443 Chesta CA, Whitten DG (1992) J Am Chem Soc 114 2188. Studies favoring a mechanism involving direct hydrogen atom transfer to form the 1,4-hydroxybiradical intermediate have recently been reported by Wang R, Chen C, Duesler E, Mariano PS (2004) J Am Chem Soc 69 1215... 

This distinction is, however, only practical. Several reaction types are not easily encompassed in the above description. For instance, Scheffer (see within this book) has provided ample examples of stereocontrolled solid-state reactions [11], while solid-state isomerizations have been studied by Coville and Levendis [12]. These processes can be explained with the reaction cavity concept, i.e. reactivity takes place in a constrained environment generated by the surrounding molecules. Relevant contributions to the field have also derived from the studies of Eckhardt [13] and those of Ohashi and collaborators [14]. 

Leibovitch M, Olovsson G, Scheffer JR, Trotter J (1998) An investigation of the Yang photocyclization reaction in the solid state asymmetric induction studies and crystal strac-ture-reactivity relationship. J Am Chem Soc 120 12755-12769... 

On his way home from the Netherlands he studied mining and metallurgy in the Harz, and in 1727 he was placed in charged of the chemical laboratory at the Bureau of Mines in Stockholm, which was then in poor financial condition. After the laboratory was sold, Brandt and his students Henrik Teofil Scheffer and Axel Fredrik Cronstedt carried on their epoch-making researches at the Royal Mint, and in 1730 Brandt became assay master of the Mint. Three years later he published a systematic investigation of arsenic and its compounds in which he showed that arsenic is a semi-metal and that white arsenic [arsenious oxide] is its calx (35). 

Scheffer, R. C. T., Poort, C. and Slot, J. W. 1980. Fate of the major zymogen granule membrane-associated glycoproteins from rat pancreas. A biochemical and immunocytochemical study. Eur. J. Cell Biol 23, 122-128. 

Scheffers DJ, Pinho MG. Bacterial cell wall synthesis new insights from localization studies. Microbiol Mol Biol Rev. 2005 69 585-607. 

The concept of absolute asymmetric synthesis using a chiral crystal was applied to unimolecular photochemistry, and now many fine examples are reported. Scheffer et al. reported elegant unimolecular absolute asymmetric transformations (Scheme 4). [19] This group demonstrated that the well-studied solution-phase di-ir-mcthane photorearrangement can also occur in the solid state. Of over 20 symmetrical and unsymmetrical dialkyl 9,10-ethanoanthracene-l 1,12-decarboxylate 22, only two compounds were found to undergo absolute asymmetric di-ir-methane... 

Olovsson, G., Scheffer, J. R., and Trotter, J. (1997) Determination of the Absolute Steric Course of an Enantioselective Single Crystal-to-Single Crystal Photorearrangement, J. Am. Chem. Soc., 119, 1462-1463,. (e) Leibovitch, M., Olovsson, G., Scheffer, J. R., and Trotter, J. (1997) Absolute configuration correlation studies in solid state organic photochemistry, PureAppl. Chem., 69, 815-823. 

There does not seem to have been much study of the stereoselectivity of cyclization of a-diketones. Scheffer and coworkers reported that 1,2-cyclodecanedione forms only the c/s-l-hydroxybicyclo-[6,2,0]decan-2-one when irradiated as crystals, but a 7 1 cis/trans ratio in benzene [59]. In solution the products proceed to cleave to a (3-ketoaldehyde, probably by Norrish type I cleavage. This problem can affect any a-hy dr oxy ketone photoproduct if light below 330 nm is used to irradiate the a-diketone. Since oc-diketones absorb above 400 nm, use of such wavelengths can avoid the problem. 

K. Nicolay, W. A. Scheffers, P. M. Bruinenberg and R. Kaptein (1982). Phosphorus-31 nuclear magnetic resonance studies of intracellular pH, phosphate compartmentation and phosphate transport in yeast. Arch. Microbiol., 133, 83-89. 

Scheffer and coworkers have intensively studied asymmetric induction for di-Tr-methane rearrangements using the ionic chiral auxiliary approach. Salt crystals of dibenzobarrelene carboxylic acid 65 with optically pure amines underwent enantioselective di-ir-methane photorearrangement to afford chiral dibenzosemi-... 

---