Hydrogen borrowing catalysis using 1° and 2° alcohols: Investigation and scope leading to α and β branched products

The alkylation of a variety of ketones using 1 degrees or 2 degrees alcohols under hydrogen borrowing catalysis is described. Initial research focused on the alpha-alkylation of cyclopropyl ketones with higher 1 degrees alcohols (i.e. larger than MeOH), leading to the formation of alpha-branched products. Our search for additional substrates with which to explore this chemistry led us to discover that di-ortho-substituted aryl ketones were also privileged scaffolds, with Ph* (C6Me5) ketones being the optimal choice. Further investigations revealed that this motif was crucial for alkylation with 2 degrees alcohols forming beta-branched products, which also provided an opportunity to study diastereoselective and intramolecular hydrogen borrowing processes. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

The study discusses the alkylation of ketones using 1 degrees or 2 degrees alcohols under hydrogen borrowing catalysis. Different substrates result in different alkylated products, with di-ortho-substituted aryl ketones being identified as a privileged scaffold. The research also explores diastereoselective and intramolecular hydrogen borrowing processes in the formation of beta-branched products.