Ozonolysis of olefins VIII. Synthesis of phenoxyacetaldehydes by ozonolysis of allylphenylethers
摘要:
A new route for the preparation of a series of phenoxyacetaldehydes (2a-j) which are useful intermediates or products, is described. It starts from the easily available allylphenylethers 1a-j which are ozonized at - 40 degrees C and further treated with dimethylsulfide to give solutions of the corresponding phenoxyacetaldehydes 2a-j; these are purified by column chromatography. Reaction of 2a-j with 1-methyl-1-phenylhydrazine leads to the corresponding hydrazones 3a-c, 3e-g, 3i, and 3j. The aldehydes can also be transformed into the stable dimethylcetals 4a, 4e, 4h, and 4i by reaction with trimethyl orthoformate.
Palladium-Catalyzed C(sp<sup>3</sup>
)−H Arylation of Primary Amines Using a Catalytic Alkyl Acetal to Form a Transient Directing Group
作者:Sahra St John-Campbell、Alex K. Ou、James A. Bull
DOI:10.1002/chem.201804515
日期:2018.12.3
requires derivatization at nitrogen with a directinggroup. Transientdirectinggroups (TDGs) permit C−H functionalization in a single operation, without needing these additional steps for directinggroup installation and removal. Here we report a palladium catalyzed γ‐C−H arylation of amines using catalytic amounts of alkyl acetals as transientactivators (e.g. commercially available (2,2‐dimethoxyethoxy)benzene)