The reactions of dimethoxycarbene (DMC; 2), which was generated in situ by thermal decomposition of 2,5-dihydro-2,2-dimethoxy-5,5-dimethyl-1,3,4-oxadiazole (1), with N-tosylated imines of xanthone and 2,3 : 6,7-dibenzosuberenone, 3a and 3d, respectively, led to different adducts with rearranged skeletons. In the case of 3a, the 1 : 1 adduct 5 as well as the 2 : 1 adduct 6 were obtained (Scheme 2).
Uncatalyzed Oxidative C−H Amination of 9,10‐Dihydro‐9‐Heteroanthracenes: A Mechanistic Study
作者:Nicolaas P. van Leest、Lars Grooten、Jarl Ivar van der Vlugt、Bas de Bruin
DOI:10.1002/chem.201900377
日期:2019.4.23
for metal‐catalyzed C−H amination processes involving nitrene transfer from iminoiodanes to dihydroheteroanthracenes. Due to the weak C−H bond, xanthene is an often‐employed substrate in mechanistic studies of C−H amination reactions, which are generally proposed to proceed via metal‐catalyzed nitrene insertion, especially for reactions involving nitrene or imido complexes that are less reactive (i
Organocatalytic nitrenoid transfer: metal-free selective intermolecular C(sp<sup>3</sup>)–H amination catalyzed by an iminium salt
作者:Logan A. Combee、Balaram Raya、Daoyong Wang、Michael K. Hilinski
DOI:10.1039/c7sc03968a
日期:——
This report details the first organocatalytic method for nitrenoid transfer and its application to intermolecular, site-selective C(sp3)–Hamination. The method utilizes a trifluoromethyl iminium salt as the catalyst, iminoiodinanes as the nitrogen source, and substrate as the limiting reagent. Activated, benzylic, and aliphatic substrates can all be selectively functionalized in yields up to 87%.
Catalytic Asymmetric α-Alkylation of Ketones and Aldehydes with <i>N</i>-Benzylic Sulfonamides through Carbon–Nitrogen Bond Cleavage
作者:Zhen-Tao Weng、Yuan Li、Shi-Kai Tian
DOI:10.1021/jo2014142
日期:2011.10.7
A range of ketones and aldehydes smoothly undergo asymmetric S(N)1 alpha-alkylation with N-benzylic sulfonamides in the presence of 10 mol % of a chiral imidazolidinone and trifluoroacetic acid to give the corresponding products in good to excellent yields and with good enantioselectivity. This chemistry has been successfully extended to the asymmetric desymmetrization of 4-substituted cyclohexanones, which exhibits greater than 99:1 diastereoselectivity and good enantioselectivity.