are described for the synthesis of the corresponding tetrahydropyridines and pyran derivatives, respectively. In particular, the use of pyridine-carboxaldehydes for aza-silyl-Prins reaction led to either a symmetrical triarylmethane or two new bicyclic compounds. 4-Fluorinated-2-substituted tetrahydropyranderivatives were also obtained in the oxa-Prins cyclization with good selectivity in favor of
Anodic oxidation of unsaturated α-stannyl ethers in Bu4NClO4âCH2Br2 results in effective cyclization and the introduction of bromide into one of the original olefinic carbons; a mechanism involving the coupling between the cyclized carbocation and Brâ generated by cathodic reduction of CH2Br2 is suggested.
Base-induced rearrangement of dihydropyran oxides: A novel synthesis of cyclic enol ethers with a hydroxy-function in the allylic position
作者:Bernd Schmidt
DOI:10.1016/s0040-4039(99)00776-5
日期:1999.6
closing metathesis of allyl-homoallyl ethers, epoxidation of the resulting dihydropyrans, and rearrangement of the dihydropyran oxides with LDA provides convenient access to 2,3-dihydropyrans with a hydroxy group in the 4-position. The products may serve as starting materials for e.g. the Carbon-Ferrier rearrangement.
Ruthenium-Catalyzed Tandem Olefin Metathesis−Oxidations
作者:Andrew A. Scholte、Mi Hyun An、Marc L. Snapper
DOI:10.1021/ol061837n
日期:2006.10.1
The utility of Grubbs' 2nd generation metathesis catalyst has been expanded by the development of two tandem olefin metathesis/oxidation protocols. These ruthenium-catalyzed processes provide cis-diols or r-hydroxy ketones from simple olefinic starting materials.
Schmidt, Bernd, Journal of the Chemical Society. Perkin transactions I, 1999, # 18, p. 2627 - 2637