Efficient One-Pot Multifunctionalization of Alkynes en Route to α- Alkoxyketones, α-Thioketones, and α-Thio Thioketals by using an Umpolung Strategy

5 years ago

Efficient One-Pot Multifunctionalization of Alkynes en Route to α- Alkoxyketones, α-Thioketones, and α-Thio Thioketals by using an Umpolung Strategy

Liming Zhang, Rongliang Zhai, Zhou Xu, Ting Liang

The use of polarized synthons is a highly desirable strategy, as it generally enables unprecedented retrosynthetic disconnections for the synthesis of unique substances. Herein, a new approach for α-oxygenated ketones, α-thioketones and α-thio thioketals via an intermolecular umpolung reaction between nucleophiles (alcohols/thioalcohols) and N-alkenoxypyridinium salts, which were generated from the corresponding alkynes, has been developed for the first time. The reactions proceed with good substrate scope and excellent functional group tolerance in one-pot manner. Applications of the products, α-oxygenated ketones, to the synthesis of other valuable synthetic moieties has also been successfully achieved. All topsy turvy: A new and broadly applicable method for the synthesis of unique α-oxygenated ketones, α-thio ketones and α-thio thioketals via umpolung reaction of nucleophiles-alcohols/thioalcohols and N-alkenoxypyridinium salts generated from alkynes in a one-pot manner is reported for the first time. The reaction is controllable and tunable with good substrates scope (46 examples) and excellent functional group tolerance (see schemes).

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201703087