Synthesis of Alkyl Halides from Aldehydes via Deformylative Halogenation
作者:Shengzong Liang、Tatsuya Kumon、Ricardo A. Angnes、Melissa Sanchez、Bo Xu、Gerald B. Hammond
DOI:10.1021/acs.orglett.9b01337
日期:2019.5.17
An unprecedented deformylative halogenation of aldehydes to alkyl halides is presented. Under oxidative conditions, 1,4-dihydropyridine (DHP), derived from an aldehyde, generated a C(sp3)- radical that coupled with a halogen radical that was generated from inexpensive and atom-economical halogen sources (NaBr, NaI, or HCl), to yield an alkyl halide. Because of the mild conditions, a wide range of functional
Synthesis of (.+-.)-Dibenzocyclooctadiene Lignans, (.+-. )-Schizandrin, (.+-.)-Gomisin A and Their Stereoisomers, Utilizing the Samarium-Grignard Reaction.
Several (±)-dibenzocyclooctadiene lignans, (±)-schizandrin (1a) (±)-gomisin A (1b), and their stereoisomers 2a and 2b, were synthesized by the samarium-Grignard reaction of the phenylpropyl bromides 4 and the phenylacetone derivative 5 to give the erythro and threo-butanols 6 and 7 followed by oxidative aryl-aryl coupling reaction of each butanol.
Transition‐Metal Free Electrophilic Aminations of Polyfunctional<i>O</i>‐2,4,6‐Trimethylbenzoyl Hydroxylamines with Zinc and Magnesium Organometallics
作者:Alisa S. Sunagatullina、Andreas Hess、Alexander Kremsmair、Yifan Li、Yi‐Hung Chen、Paul Knochel
DOI:10.1002/anie.202304445
日期:2023.7.24
Various zinc and magnesium reagents were successfully aminated using O-2,4,6-trimethylbenzoyl hydroxylamines (O-TBHAs) leading to the corresponding tertiary alkyl amines in 52–99 % yield without any additional transition-metal catalyst. This reaction was extended to the preparation of optically enriched amines (up to 88 % ee) starting from enantioenriched secondary alkylmagnesium reagents of the type
describes an environmentally friendly strategy for thiolation and trifluoromethylthiolation of Hantzsch esters. The alkyl radical could be generated smoothly without any photocatalyst via modification of chromophores of alkyl dihydropyridines and wavelength of light. Besides, a broad alkyl dihydropyridine substrate scope and high functional group tolerance are observed. In addition, the modulation of