Herein a new synthetic route to 1,2-amino alcohols is presented by using C-H amidation of sp(3) methyl C-Hbonds as a key step. Readily available alcohols were employed as starting materials after converting them to removable ketoxime chelating groups. Iridium catalysts were found to be effective for the C-H amidation, and LAH reduction was then used to furnish beta-amino alcohol products.
Rhodium(<scp>iii</scp>)-catalyzed directed amidation of unactivated C(sp<sup>3</sup>)–H bonds to afford 1,2-amino alcohol derivatives
作者:Yi Dong、Jiajing Chen、Heng Xu
DOI:10.1039/c8cc05637d
日期:——
A rhodium-catalyzed directed C(sp3)–H amidation to afford 1,2-amino alcohol oxime derivatives has been developed with good yields and a broad substrate scope. In previous methods for this type of reaction, 1-arylethan-1-ol oxime analogues were challenging substrates owing to strong competition fromC(sp2)–H bondactivation. This Rh-catalyzed C–H activation method overcomes the limitation of competitive
Copper-Catalyzed Intermolecular Amidation and Imidation of Unactivated Alkanes
作者:Ba L. Tran、Bijie Li、Matthias Driess、John F. Hartwig
DOI:10.1021/ja411912p
日期:2014.2.12
evidenced by the catalytic reaction of cyclohexane with benzamide in the presence of CBr4, which formed exclusively bromocyclohexane. Furthermore, stoichiometric reactions of [(phen)Cu(phth)2] with tBuOOtBu and (Ph(Me)2CO)2 at 100 °C without cyclohexane afforded N-methylphthalimide (Me-phth) from β-Me scission of the alkoxyradicals to form a methylradical. Separate reactions of cyclohexane and d12-cyclohexane
Selective introduction of fluorine into molecules by the cleavage of inert C−H bonds is of central academic and synthetic interest, yet remains challenging. Given the central role of alcohols in organic chemistry as the most ubiquitous building blocks, a versatile and selectiveC(sp3)−H and C(sp2)−H fluorination of simple alcohols, enabled by novel designed exo‐directing groups, is described. C(sp2)−H
Catalytic Functionalization of Unactivated sp<sup>3</sup> C–H Bonds via <i>exo</i>-Directing Groups: Synthesis of Chemically Differentiated 1,2-Diols
作者:Zhi Ren、Fanyang Mo、Guangbin Dong
DOI:10.1021/ja3082186
日期:2012.10.17
describe a Pd-catalyzed site-selective functionalization of unactivated aliphatic C-H bonds, providing chemically differentiated 1,2-diols from monoalcohol derivatives. The oxime was employed as both a directing group (DG) and an alcohol surrogate for this transformation. As demonstrated in a range of substrates, the C-H bonds β to the oxime group are selectively oxidized. Besides activation of the methyl