146450-45-5Relevant academic research and scientific papers
Total Synthesis and Structural Reassignment of Lyngbyaloside C Highlighted by Intermolecular Ketene Esterification
Chang, Chia-Fu,Stefan, Eric,Taylor, Richard E.
, p. 10681 - 10686 (2015)
Lyngbyaloside C, a classic macrolide, isolated from Lyngbya bouilloni, has shown moderate anticancer activity against several cancer cell lines. Here, we report the first total synthesis and stereochemical configuration reassignment of lyngbyaloside C. Th
A formal total synthesis of anti-Helicobacter pylori agent (+)-spirolaxine methyl ether
Gadakh, Sunita K.,Sudalai, Arumugam
supporting information, p. 25 - 28 (2015/12/23)
A convergent, formal enantioselective synthesis of anti-Helicobacter pylori agent, (+)-spirolaxine methyl ether 2 has been achieved in high enantiomeric purity starting from commercially available 1,5-pentanediol. The strategy mainly comprises of the Noyori's asymmetric reduction and Brown allylation/Cu-catalyzed lactonization as the key step for the construction of key chiral intermediates, spiroketal 3 and phthalide fragment 4.
Folding strain stereocontrol in cyclohexane ring formation by means of an intramolecular ester enolate alkylation reaction
Tokoroyama, Takashi,Kusaka, Hisashi
, p. 2487 - 2502 (2007/10/03)
Diastereoselectivity in the cyclization of ethyl 7-bromo-2-methylheptanoates with an additional substituent at various positions in the chain, by LDA treatment, was investigated in connection with the concept of folding strain stereocontrol. Cyclization of 3-, 4-, and 6-methyl-substituted substrates revealed high selectivity, which demonstrates the prevalence of folding strain stereocontrol and the usefulness of this approach for stereoselective ring construction. In particular, reactions of the latter two substrates resulted in the stereodivergent preparation of diastereomeric 1,3-dimethylcyclohexanecarboxylates. In the case of the 5-methyl-substituted substrate, the selectivity of ring closure was only moderate. 1H and 13C NMR spectroscopic data were useful for determining the conformation of 1-methylcyclohexanecarboxylate derivatives. The origin of the diastereoselectivity was examined through the qualitative comparison of the strain in the diastereomeric folding in the transition state. Various factors that might affect stereoselectivity were examined in the cyclization of 5-substituted substrates to better understand this concept. As predicted, the selectivity increased as the substituent became bulkier: Ph Me ≈ Et ≤ i-Pr t-Bu. The effects of other factors - solvent, base counter cation, and leaving group - on selectivity agree with results predicted from the reactivity-selectivity relationship.
Heterocycle formation through aza-annulation: A stereochemically controlled route to (±)-lupinine
Paulvannan,Schwarz,Stille
, p. 215 - 218 (2007/10/02)
The aza-annulation of an acyclic β-enaminoester with acryloyl chloride was found to be a very efficient method for nitrogen heterocycle formation. Stereospecific hydrogenation of the unsaturated dihydropyridone generated from aza-annulation gave a single disubstituted lactam product. The cis stereochemical relationship of the substituents was confirmed by transformation of the lactam to (±)-lupinine.
