Neighboring group participation in Lewis acid-promoted [3 + 4] and [3 + 5] annulations. The synthesis of oxabicyclo[3.n.1]alkan-3-ones
作者:Gary A. Molander、Kimberly O. Cameron
DOI:10.1021/ja00056a002
日期:1993.2
2-(alkoxycarbon)-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 regioncontrol is observed, and good to excellent stereochemicalcontrol can be achieved at virtually every position on the new carbocycles. Intramolecular neighboringgroupparticipation is proposed to explain the unusually high selectivities attained in the annulation
<i>N</i>-phenyl-substituted pyrrolidines, piperidines and azabicyclics by a tandem reduction-double reductive amination reaction
作者:Richard A. Bunce、Derrick M. Herron、Jason R. Lewis、Sharadsrikar V. Kotturi
DOI:10.1002/jhet.5570400115
日期:2003.1
formed in high yield and are easily purified. The method has also been extended to the synthesis of fused N-phenylazabicyclics from 2-(3-oxo-propyl)cycloalkanones. A high degree of diastereoselectivity for the trans-fused product is observed in substrates having an ester group α to the cycloalkanone carbonyl. Bicyclic precursors lacking this ester group give mixtures of cis and trans products. Finally
Cooperative Catalysis of Samarium Diiodide and Mercaptan in a Stereoselective One-Pot Transformation of 5-Oxopentanals into δ-Lactones
作者:Jue-Liang Hsu、Chao-Tsen Chen、Jim-Min Fang
DOI:10.1021/ol9911526
日期:1999.12.1
[GRAPHICS]We demonstrate a general method for conversion of various 5-oxopentanals to substituted delta-lactones and 1-oxa-2-decalones by the synergistic catalysis of samarium diiodide and 2-propanethiol (or disulfide), The deliberate use of mercaptan is advantageous to facilitate the catalytic cycle, This method shows high stereoselectivities, and an enantioselective procedure is feasible by using the chiral mercaptan (1R,2S)-1 phenyl-2-(N-acetamido)propanethiol as a promoter.
Bis(trimethylsilyl) enol ethers as 1,3-dianion equivalents: Regiocontrolled [3+4] and [3+5] annulation reactions
作者:Gary A. Molander、Steven W. Andrews
DOI:10.1016/s0040-4039(01)80396-8
日期:——
MOLANDER, GARY A.;ANDREWS, STEVEN W., TETRAHEDRON LETT., 30,(1989) N8, C. 2351-2354