Showing papers in "Tetrahedron in 1985"

TL;DR: In this article, a theoretical study of the relative rates and the regio-and stereo-chemistry of ring closure of a variety of alkenyl radicals was performed using MM2 force-field calculations.

TL;DR: In this article, the causative agents of a new type of shellfish poisoning, named diarrhea-shellfish poisoning were identified, namely, 35(S)-methylokadaic acid, 7-O-acyl derivatives of 35S-methylkadaic acids, two novel polyether lactones named pectenotoxin-1 and -2 have been isolated and had their structures determined.

TL;DR: The aliphatic and alicyclic esters of N-hydroxypyridine-2-thione are readily reduced by tributylstannane in a radical chain reaction to furnish nor-alkanes as discussed by the authors.

TL;DR: Generation des ions Nacyliminiums and syntheses de leurs precurseurs; amidoalkylations intramoleculaires avec des π-nucleophiles aromatiques; reactions de π nucleophilia non aromatique; utilisation des composes a methylene actif; reactions pericycliques

TL;DR: A new index of aromatic character has been devised based upon a statistical evaluation of the deviations in peripheral bond orders as discussed by the authors, which can be derived readily from experimentally determined bond lengths.

TL;DR: In this article, a synthese traitant du classement de ces composes et de leurs reactions de cycloaddition is described, based on a syntactique traitant.

TL;DR: In this paper, the formation of cyclopentenones from alkynes, plus alkenes and cobalt carbonyl is reviewed, with special attention to the scope and the regio- and stereoselectivity of the reaction.

TL;DR: In this paper, a free radical (or "one-electron") methodology for carbon-carbon bond forming reactions using allylstannanes is described in detail, which has the advantages of tolerating quite complex functionality in the substrate and of being nearly stoichiometric in reagents, and not requiring extensive experimentation for application to new substrates.

TL;DR: In this paper, the authors show that the (4+2)-cycloadditions of singlet oxygen to these furans yield the corresponding monomeric unsaturated secondary ozonides.

TL;DR: In this paper, a dependence between the acidity and basicity parameters of water/alcohol mixtures with ten organic solvents has been found, and the dependence between these parameters and E N T on B KT dependence is more complex even if these parameters are purified from nonspecific solute/solvent interactions.

TL;DR: In this paper, the 11B NMR data for borate esters of polyols and polyhydroxycarboxylates in aqueous alkaline solution were presented.

TL;DR: In this article, the experimental and theoretical attempts to determine the equilibrium bond angle in the 3B1 ground state and the 1A1-3B1 energy gap between the lowest two states of the methylene molecule are reviewed.

TL;DR: In this article, a mechanistic hypothesis to explain the observed stereospecificity is presented, which is suitable for straightforward elaboration into coriolin and hirsutic acid precursors.

TL;DR: In this article, the oxidative dimerization of 2-naphthol was studied by means with several copper(II)amine complexes as oxidants using primary amines.

TL;DR: Extraction of the dried fruits from the cannon ball tree, Couroupita guianensis Aubl, yielded 6,12-dihydro-6, 12-dioxoindolo[2,1-b ]quinazoline (tryptanthrin), 1a as well as indigo ( 7 ) indirubin ( 8a ) and isatin this article.

TL;DR: The in vivo incorporation of mevalonolactone specifically into the terpene portion of a sesquiterpene hydroquinone is reported for the soft coral Sinularia capillosa Eudesma -4, 7(11)- diene -8β- ol (20 ) and the corresponding 8-keto derivative (21 ) for the first time as discussed by the authors.

TL;DR: In this article, the MP2/3-21G basis set was used for cycloadditions of CF2 and CCl2 with ethylene and substituted alkenes.

TL;DR: In this article, a diastereo and enantioselective synthesis of α-amino-γ-oxo acid esters by reaction of acyliminoacetates with enamines is described.

TL;DR: In this article, the transformation of the organopalladium compound (3) into the corresponding deuteriated, chlorinated, or oxidized derivatives (7), (8), or (9), (11), and (12) respectively.

TL;DR: In this article, a novel radical-initiated polyolefinic cyclization approach to linear condensed cyclopentanoids is reported, executed in three stages: (1) Sn2′-anti opening of a vinyl lactone, (2) rapid elaboration to a cyclization precursor, and (3) single step tandem radical cyclization to produce a cis-anticis tricyclo[3.3.0]undecane.

TL;DR: The phenylseleno group (PhSe) has been shown to be a useful and versatile functionality in many natural products synthesis as mentioned in this paper, and it can be readily oxidized to the corresponding selenoxide(PhSe(O), which undergoes β-hydrogen abstraction and syn-elimination to form olefins, under relatively mild conditions.

TL;DR: In this paper, the synthesis of anthracyclinones via tandem cycloaddition/annulation reactions with Fischer carbene complexes has been examined and the potential of these reactions for coupling to organochromium compounds has been demonstrated.