[show abstract][hide abstract] ABSTRACT: [reaction: see text] A novel chiral monodentate spiro phenylphospholane ligand 4 was prepared from a readily accessible, enantiomerically pure 1,1'-spirobiindane-7,7'-diol in high yield. This ligand has proven to be efficient for Pd-catalyzed enantioselective allylation of aldehydes with allylic alcohols. Aromatic, heteroaromatic, and aliphatic aldehydes gave homoallylic alcohols in good enantioselectivities (up to 83% ee) and excellent anti diastereoselectivities (up to 99:1 dr).
[show abstract][hide abstract] ABSTRACT: An account is given of the development of the SHELX system of computer programs from SHELX-76 to the present day. In addition to identifying useful innovations that have come into general use through their implementation in SHELX, a critical analysis is presented of the less-successful features, missed opportunities and desirable improvements for future releases of the software. An attempt is made to understand how a program originally designed for photographic intensity data, punched cards and computers over 10000 times slower than an average modern personal computer has managed to survive for so long. SHELXL is the most widely used program for small-molecule refinement and SHELXS and SHELXD are often employed for structure solution despite the availability of objectively superior programs. SHELXL also finds a niche for the refinement of macromolecules against high-resolution or twinned data; SHELXPRO acts as an interface for macromolecular applications. SHELXC, SHELXD and SHELXE are proving useful for the experimental phasing of macromolecules, especially because they are fast and robust and so are often employed in pipelines for high-throughput phasing. This paper could serve as a general literature citation when one or more of the open-source SHELX programs (and the Bruker AXS version SHELXTL) are employed in the course of a crystal-structure determination.
Acta Crystallographica Section A Foundations of Crystallography 02/2008; 64(Pt 1):112-22. · 2.24 Impact Factor
[show abstract][hide abstract] ABSTRACT: Bis-cyclization reaction of the 1,5-diaryl-3-pentanones catalyzed by heteropoly acids (HPAs) was examined for the first time, and a series of spirobiindanes were synthesized. 1,5-Diaryl-3-pentanones were refluxed and dehydrated in toluene in the presence of 0.15equiv of a heteropoly acid to furnish spirobiindanes in moderate to high yield. For the known 4,4′-dibromo-7,7′-dimethoxy-1,1′-spirobiindane, the yield was upgraded from 66% to 80%.
Tetrahedron Letters - TETRAHEDRON LETT. 01/2006; 47(26):4343-4345.
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.