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
Formation, Alkylation, and Hydrolysis of Chiral Nonracemic <i>N</i>-Amino Cyclic Carbamate Hydrazones: An Approach to the Enantioselective α-Alkylation of Ketones
作者:Uyen Huynh、Stacey L. McDonald、Daniel Lim、Md. Nasir Uddin、Sarah E. Wengryniuk、Sumit Dey、Don M. Coltart
DOI:10.1021/acs.joc.8b00655
日期:2018.11.2
as α-functionalized ketones or derivatives thereof. We previously reported our preliminary studies on the development of a new enantioselective ketone α-alkylation procedure using N-amino cyclic carbamate (ACC) auxiliaries. In comparison to other auxiliary-based methods, ACC alkylation offers a number of advantages and is both highly enantioselective and high yielding. Herein, we provide a full account
Palladium(II)-catalyzed claisen rearrangement of allyl vinyl ethers
作者:J.L van der Baan、F Bickelhaupt
DOI:10.1016/s0040-4039(00)85449-0
日期:1986.1
The Claisen rearrangement of allyl vinyl ethers is catalyzed by PdCl2(CH3CN)2, provided that alkyl substituents protect the vinyl ether double bond from coordination by the metal catalyst.
A new sequential reductive coupling process promoted by samarium(II) iodide is described. Cascade epoxide ring opening and ketyl radical olefin cyclization leads to a variety of cis-1,3-cyclopentanediols and cis-1,3-cyclohexanediols in good yields and with high diastereoselectivity.
Direct α-allylation of a variety of ketones and aldehydes with 2-allylisourea took place in the presence of a catalytic amount of a palladium(0) complex under neutral and mild conditions. Scope and limitations of this novel method have been investigated.