Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: CAS:6221-55-2 (bicyclo[3.2.1]octane)
 92 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

(1R*,3R*,7S*,9S*)-1,4,4-Trimethyl-9-(tert-butyldimethylsilyloxy)-e xo-11-oxatricyclo[5.3.1.0(2,6)]-undecan-3-ol, C19H36O3Si, Mr = 340.90, orthorhombic, Pbca, a = 10.411 (3), b = 13.275 (3), c = 29.085 (10) A, V = 4019 (2) A3, Z = 8, Dx (130 K) = 1.13 g cm-3, lambda(Mo K alpha) = 0.71069 A, mu = 1.24 cm-1, F(000) = 1504, T = 130 K, R = 0.077 for 1005 observed reflections with I greater than 3 sigma(I). The compound, whose connectivity was not readily apparent from spectroscopic and chemical information alone, possesses a tricyclic framework containing an O-bridged bicyclo[3.2.1]octane fused in a cis-exo manner to a cyclopentanol ring. Most noteworthy is the considerably lower polarity of this compound relative to its opposite cyclopentanol stereoisomer. The close proximity [2.78 (1) A] of the bridging O atom in the [3.2.1] system to the hydroxyl O atom on the five-membered ring is suggestive of an intramolecular hydrogen bond, although the H atom could not be located.
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PMID:Structure of an unusually non-polar hydroxy ether. 206 68

Detailed experimental approaches toward the pentacyclic Stemona alkaloids tuberostemonine and didehydrotuberostemonine and the close analogue 13-epituberostemonine are described. The syntheses originate with a hydroindolinone derivative that can be obtained on a large scale in a single step from carbobenzoxy-protected l-tyrosine. Highlights of the conversion of this hydroindolinone to the target structures are the three-fold use of ruthenium catalysts, first in azepine ring-closing metathesis and then in alkene isomerization and cross-metathesis propenyl-vinyl exchange, as well as the stereoselective attachment of a gamma-butyrolactone ring to a tetracycle core structure by use of a lithiated asymmetric bicyclo[3.2.1]octane (ABO) ortho ester. Structural analysis by density functional theory (DFT) methods revealed that the ease of oxidation of the natural product is likely due to the conformational preferences of the pyrrolidine and the fused cyclohexane rings.
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PMID:Asymmetric total syntheses of tuberostemonine, didehydrotuberostemonine, and 13-epituberostemonine. 1563 72

The asymmetric total synthesis of farnesin, a rearranged ent-kaurenoid, was achieved through a convergent approach involving photo-Nazarov and intramolecular aldol cyclizations to build the syn-syn-syn hydrofluorenol ABC ring system and bicyclo[3.2.1]octane CD ring system in the first application of a UV-light-induced excited-state Nazarov cyclization of a non-aromatic dicyclic divinyl ketone in a total synthesis. Unlike the conventional acid-promoted ground-state Nazarov reaction, the excited-state Nazarov reaction enables stereospecific formation of the highly strained syn-syn-syn-fused hydrofluorenone scaffold through a disrotatory cyclization.
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PMID:Total Synthesis of Farnesin through an Excited-State Nazarov Reaction. 3205 28