53847-17-9Relevant academic research and scientific papers
Studies on the Himbert intramolecular arene/allene diels-alder cycloaddition. Mechanistic studies and expansion of scope to all-carbon tethers
Schmidt, Yvonne,Lam, Jonathan K.,Pham, Hung V.,Houk,Vanderwal, Christopher D.
, p. 7339 - 7348 (2013/06/27)
The unusual intramolecular arene/allene cycloaddition described 30 years ago by Himbert permits rapid access to strained polycyclic compounds that offer great potential for the synthesis of complex scaffolds. To more fully understand the mechanism of this
Complete diastereocontrol in intramolecular 1,3-dipolar cycloadditions of 2-substituted 5-hexenyl and 5-heptenyl nitrones: Application to the synthesis of the β-lactam antibiotic 1β-methylthienamycin
Jung,Vu
, p. 4427 - 4433 (2007/10/03)
The diastereoselectivity of intramolecular 1,3-dipolar cycloadditions of 2-substituted 5-hexenyl and 5-heptenyl nitrones to give 6-substituted and 3,6-disubstituted perhydrocyclopenta[c]isoxazoles has been investigated. An alkyl or aryl substituent at C2 completely controls the stereochemistry of the ring juncture and, in the case of the 5-heptenyl systems, also the stereochemistry of the 3-methyl group. Thus one stereocenter controls the formation of the other three to give a product with four contiguous stereocenters. The use of an ethylene ketal substituent in these systems allows the reaction to be carried out at much lower temperatures, an example of the gem-dialkoxy effect. This cycloaddition process has been used in an efficient formal total synthesis of the potent β-lactam antibiotic, 1β-methylthienamycin.
Neighboring group participation in Lewis acid-promoted [3 + 4] and [3 + 5] annulations. The synthesis of oxabicyclo[3.n.1]alkan-3-ones
Molander, Gary A.,Camera, Kimberly O.
, p. 830 - 846 (2007/10/02)
Lewis acids are employed as catalysts in the annulation of 1,4- and 1,5-dicarbonyl dielectrophiles with bis(trimethylsilyl) end ethers of β-diketones and β-keto esters. A variety of 2-(alkoxycarbonyl)-m-oxabicyclo[3.n.1]alkan-3-ones can be constructed by this process in which two new carbon-carbon bonds are generated. Unusually high regiocontrol is observed, and good to excellent stereochemical control can be achieved at virtually every position on the new carbocycles. Intramolecular neighboring group participation is proposed to explain the unusually high selectivities attained in the annulation reaction.
