Showing papers in "Tetrahedron in 1983"

TL;DR: On etudie successivement les systemes aza-1 butadiene, triazabutadiene and diaza- 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,

TL;DR: In this article, an empirical formulation is presented to predict the stereochemistry of major osmylation products of allylic alcohols and their derivatives, and an empirical model is proposed to predict their stereochemistry.

TL;DR: In this paper, the parent calixarenes have been converted to various derivatives, including the methyl, ethyl, allyl, benzyl and trimethylsilyl ethers and the acetates.

TL;DR: In this article, negative anionic hyperconjugation was studied for anions and related neutral systems using ab initio split valence basis sets, 3−21+G and 4−31+G, which are augmented by a set of diffuse s and p functions on the non-hydrogen atoms.

TL;DR: In this article, the authors propose the generation of an intermediaire radicalaire par transfert d'electron, which is based on Desoxygenation photolytique.

TL;DR: In this article, the C-Si bonds in organosilicon fluorides, K 2 (RSiF 5 ] and R n SiF 4-n, are cleaved by m-chloroperbenzoic acid (MCPBA) in DMF to give the corresponding alcohols in high yields.

TL;DR: In this article, transition state models are discussed that could explain the exceptionally high asymmetric induction and the predictability of the induced configuration of bis-lactim ethers with high diastereoface differentiation.

TL;DR: In this article, anionic activation of Si-H, Si-O and Si-N bonds by fluoride ions under heterogeneous conditions is reported, which constitutes an extension of the Michael reaction since the addition occurs even with crowded ketones.

TL;DR: The structure of an alkaloid isolated from Rhizoctonia leguminicola, which was previously assigned as 3,4.5-trihydroxy octahydro-1-pyrindine, has now been revised to (1S,2R,8R, 8aR)-1,2,8-trihedroxyoctahydronindolizine as discussed by the authors.

TL;DR: In this article, the influence of the molecular structure of catalysts and of their secondary conformation on the enantioselectivity of chalcone and other electron-poor olefins in a triphase system was examined.

TL;DR: Cyanotrimethylsilane as mentioned in this paper adds to some ⇌,β-unsaturated ketones in conjugate manner under the catalytic action of Lewis acids such as triethylaluminium, aluminium chloride, and SnCl 2.

TL;DR: In this paper, a regiospecific [3 + 2] annulation approach to highly substituted 5-membered carbocycles has been developed, which involves the reaction of (trimethylsilyl)allenes with electron-deficient alkenes and alkynes in the presence of titanium tetrachloride to afford, in a single step, a functionalized and highly substituted TMS-cyclopentene derivative.

TL;DR: Meso-tetrakis (3,5-di-tert-butyl-4-hydroxyphenyl)porphyrin (1a) undergoes rapid, non-photosensitised, aerial oxidation in basic solutions as discussed by the authors.

TL;DR: In this article, the 3-fluoropyridine metallation regioselectivity was studied in terms of the thermodynamic control of the metallization process.

TL;DR: In this paper, an attempt was made to improve the tendency of Allinger's latest empirical force field MM2 to underestimate barrier heights of rotation about C-C single bonds, and the modified force field correctly reproduced chair-chair interconversion barrier of all-cis-l, 2,3,4,5,6-hexamethylcyclohexane (calc. 16.7, obsd. 17.426 A.

TL;DR: In this article, it was shown that at 100°C, aliphatic and aromatic thioaldehydes without electronic bias are shown to undergo addition reactions to both ALH and aromatic 1,3-dienes.

TL;DR: Two successful synthetic routes to trichostatin A were described in this paper, one using the γ-alkylation of a silyl dienol ether, the other using a Silyl-protected cyanohydrin anion.

TL;DR: The effect of doping Lindlar catalyst with different metal salts on selectivity during semihydrogenation of some acetylenes to the corresponding olefins has been studied in this article.