https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

The Diels-Alder reaction has both enabled and shaped the art and science of total synthesis over the last few decades to an extent which, arguably, has yet to be eclipsed by any other transformation in the current synthetic repertoire. With myriad applications of this magnificent pericyclic reaction, often as a crucial element in elegant and programmed cascade sequences facilitating complex molecule construction, the Diels-Alder cycloaddition has afforded numerous and unparalleled solutions to a diverse range of synthetic puzzles provided by nature in the form of natural products. In celebration of the 100th anniversary of Alder's birth, selected examples of the awesome power of the reaction he helped to discover are discussed in this review in the context of total synthesis to illustrate its overall versatility and underscore its vast potential which has yet to be fully realized.

https://www.ch.ic.ac.uk/local/organic/pericyclic/DA.pdf

The Diels--Alder reaction in total synthesis.

Solvent-free organic synthesis , Solvent-free organic synthesis , کتابخانه دیجیتال جندی شاپور اهواز

Solvent-free organic synthesis

International Tables for X-Ray Crystallography (Published for the International Union of Crystallography.) Vol. 1: Symmetry Groups. Edited by Norman F. M. Henry and Kathleen Lonsdale. Pp. xi + 558. (Birmingham: Kynoch Press, 1952.) 105s.

/pdf/international-tables-for-x-ray-crystallography-1t8sk98xrd.pdf

International Tables for X-Ray Crystallography

This critical review begins with a brief, but essential, introduction to the special nature of liquid crystal materials, their peculiar properties, and their commercial applications, followed by an introductory insight into the remarkable nature of the fluoro substituent, and its fascinating influence on the properties of organic compounds. However, the main focus of the review is to discuss the enormous amount of exciting research on fluorinated liquid crystals that has been reported. The small size of the fluoro substituent enables its incorporation into all types of liquid crystal, including calamitic, discotic, banana, lyotropic, and polymers, without ruining the liquid crystalline nature of the material. However the fluoro substituent is larger than hydrogen, and hence causes a significant steric effect, which combined with the high polarity, confers many fascinating, and often remarkable, modifications to melting point, mesophase morphology and transition temperatures, and the many other very important physical properties, such as dielectric anisotropy, optical anisotropy, and visco-elastic properties. There are many different positions within a liquid crystal structure where a fluoro substituent can be located, including (i) a terminal position, (ii) within a terminal chain, as a semi-fluorinated or as a perfluorinated chain, or as one fluoro substituent at a chiral centre, (iii) as part of a linking group, and (iv) a lateral position in the core section. Such variety enables the interesting and advantageous tailoring of properties, both for the fundamental purposes of establishing structure–property relationships, and for materials targeted towards commercially-successful liquid crystal display applications.

Fluorinated liquid crystals – properties and applications

Vibrational mode-specific tunneling splittings in the Ã states of deuterated tropolones

Metabolites of Clitocybe illudens. IV. Illudalic acid, a sesquiterpenoid, and illudinine, a sesquiterpenoid alkaloid.

One of the photocycloadducts obtained during methyl 2,4-dioxopentanoate to isoprene was converted to optically active iridoids. Using a CrCl2 reductive-coupling reaction, proper combinations of two kinds of enantiomeric iridoids, 1-iriden-7-al and 9-benzyloxy-7-chloro-1-iridene, produced versatile intermediates for various types of 5-8-5-membered tricyclic natural products. From one such product, fusicocca-2,8,10(14)-triene (1) was synthesized by sequential transformations.

Synthetic Photochemistry. XXXIV. Synthetic Strategy of 5-8-5-Membered Tricyclic Higher Terpenoids Based on the Condensation of Two Optically-Active Iridoids, C10-Synthons Obtained from Photo-Cycloadduct of Methyl 2,4-Dioxopentanoate–Isoprene, and Its Application to a Synthesis of the Basic Carbon Skeleton of Fusicoccane

Hitoshi Takeshita

Papers

Vibrational mode-specific tunneling splittings in the Ã states of deuterated tropolones

Metabolites of Clitocybe illudens. IV. Illudalic acid, a sesquiterpenoid, and illudinine, a sesquiterpenoid alkaloid.

Synthesis of 2-(alkanoyloxy)-5-alkoxytropones. Novel monocyclic rod-type liquid crystals

Synthesis and metallophilic properties of troponoid thiocrown ethers