Mild Debenzylation of Aryl
Benzyl Ether with BCl3 in the Presence of Pentamethylbenzene
as a Non-Lewis-Basic Cation Scavenger
摘要:
Scope and limitations of the debenzylation conditions for aryl benzyl ether, which was developed during our synthetic studies on yatakemycin, were investigated. The chemoselective debenzylation proceeds at low temperature with a combination of BCl(3) and pentamethylbenzene as a cation scavenger in the presence of various functional groups.
Biocatalysis provides an attractive approach to facilitate synthetic reactions in aqueous media. Motivated by the discovery of promiscuous aminolysis activity of esterases, we exploited the esterase from Pyrobaculum calidifontis VA1 (PestE) for the synthesis of carbamates from different aliphatic, aromatic, and arylaliphatic amines and a set of carbonates such as dimethyl‐, dibenzyl‐, or diallyl carbonate. Thus, aniline and benzylamine derivatives, aliphatic and even secondary amines could be efficiently converted into the corresponding benzyloxycarbonyl (Cbz)‐ or allyloxycarbonyl (Alloc)‐protected products in bulk water, with (isolated) yields of up to 99 %.