The stereochemistry of ethyleneimines fused to six-membered rings (original) (raw)
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A New, Stereoselective, Ring-Forming Reaction of 1, 2-Ethanedithiol with N-Acylated Indoles
The Journal of Organic …, 2007
Notes, Brief Communications, and JOCSynopses have length limits. The abstract, introductory remarks, and results and discussion of a Note do not exceed 3000 words; the limit for a Brief Communication is 2000 words. For Notes and Brief Communications, tables and graphics (figures, reaction schemes, and chemical structure graphics) are counted against the word-count limits at the rate of 50 words per vertical inch for one-column (<3.3 inches wide) items, and 100 words per vertical inch for wider items. There are no word-count limits on the experimental section. For information about the length limit for JOCSynopses see section 2.3.3.
ChemInform, 2008
Notes, Brief Communications, and JOCSynopses have length limits. The abstract, introductory remarks, and results and discussion of a Note do not exceed 3000 words; the limit for a Brief Communication is 2000 words. For Notes and Brief Communications, tables and graphics (figures, reaction schemes, and chemical structure graphics) are counted against the word-count limits at the rate of 50 words per vertical inch for one-column (<3.3 inches wide) items, and 100 words per vertical inch for wider items. There are no word-count limits on the experimental section. For information about the length limit for JOCSynopses see section 2.3.3.
Helvetica Chimica Acta, 2005
c) Max-Planck-Institut für Kohlenforschung, D-45470 Mülheim an der Ruhr A novel approach for the synthesis of carbene adducts 9a/9b and 10/11 is reported. Identification of the geometric and positional isomers of carbene addition was carried out by reversed-phase HPLC, and the establishment of the structure and configuration of 9a/9b was performed by means of 2D-NMR. Introduction.-The liquid crystals used in modern display devices are calamitic liquid crystals. A huge number of such liquid crystals have been synthesized and used in practical displays [1] [2]. It is known that by modification of the basic structures of liquid-crystal molecules, a wide range of property changes affecting the liquid-crystal behavior of the materials can be produced. The core unit presently used in most of the calamitic liquid crystals is cyclohexane, phenylcyclohexane, etc. Therefore, various modifications in the basic cyclohexane, bicyclohexyl and phenylbicyclohexyl structures have been made recently to overcome problems of electrooptic and viscoelastic parameters [3] [4]. We developed a completely new core unit-the perhydroazulene unit [5]. It is flat and allows introduction of numerous substituents and its configuration can be affected by the central junction as well as by the relative orientation of the substituents. The key step in the synthesis of such core units is the carbene addition to the C=C bond of the Birch-reduction product of appropriate indane (= 2,3-dihydro-1H-indene) derivatives and subsequent isolation of a single isomer. Our studies on similar compounds indicated that exclusive formation of only one stereoisomer from carbene addition is rarely observed. We now isolated two geometric isomers 9a/9b (carbene addition to the peripheral C=C bond of the cyclohexa-1,4-diene moiety of the Birch-reduction product) and their two positional isomers 10/11 (carbene addition to the corresponding fusion-site C=C bond). Keehn et al. [6] reported the synthesis of a similar mixture of carbene adducts where they used a fractional-distillation method to separate a 4 : 1 mixture of two positional isomers. However, nothing was mentioned about the formation and separation of geometric isomers. Lightner et al. [7] reported similar carbene-addition reactions where they could separate one major isomer in 45% yield. But they did not report any details about the formation and separation of other isomers or what happened with the remainder 55% of the starting material, a corresponding Birch-reduction product.
Synthesis of fused ethyleneimines from cyclic olefins
Tetrahedron, 1964
The stereospecific addition of iodine isocyanate to cyclic olefins leads via trans iodo isocyanates to trans iodo carbamates in good yields. The latter are converted by reaction with base into ethyleneimines.
J Org Chem, 1985
We set out to describe a new and versatile method for transforming steroidal five-and six-membered cyclic ketones as starting materials into steroidal cyclic ethers with the same ring size via four steps; Baeyer-Villiger oxidation of a steroidal ketone to a lactone followed by ita reduction with DIBAL gives the corresponding lactol. The irradiation of the hypoiodite generated in situ by means of the reaction of the lactol by an excess of mercury oxide-iodine and pyridine in benzene gives formates arising from a regiospecific @-scission of the C-C bond. These formates can readily be transformed into oxasteroids by treatment with a complex metal hydride or methyllithium. By this new method a variety of steroidal cyclic ketones were transformed into the corresponding cyclic ethers in good overall yields. The stereochemical integrity of the chiral center adjacent to the carbonyl group of the starting cyclic ketones is maintained throughout this transformation. (1) Part 76. Suginome, H.; Liu, C. F.; Tokuda, M.; Furusaki, A. J . (2) Preliminary communication: Suginome, H.; Yamada, S. Tetrahe-Chem.