The First Simple Method of Protection of Hydroxy Compounds as their O-Boc Derivatives under Lewis Acid Catalysis

Abstract

The first Lewis acid catalyzed protection of alcohols as Boc derivatives is described. Zinc acetate is a very efficient catalyst for this transformation and the reaction can be applied to primary, secondary and aromatic alcohols, providing the first example of a generally applicable method.

Recent Development about the Use of Pyrocarbonates as Activator in Organic Synthesis: A Review

“…The reaction is general and can be applied to primary and secondary alcohols, various substituted phenols and naphthol (Scheme 8) [32]. The nature of the substituent on the aromatic ring seems to influence the reaction rate, in fact an electron-donating group fastened the reaction with respect to an electron-withdrawing one ( vs. 17 h), exactly the opposite with respect to the base catalyzed reaction.…”

Asymmetric Synthesis of Atorvastatin Calcium through Intramolecular Oxidative Oxygen‐Nucleophilic Bromocyclization

“…However, treatment of 13 with tert ‐butyl chloroformate in pyridine at room temperature for 2 d resulted in no reaction. In contrast, treatment with Boc 2 O in the presence of Zn(OAc) 2 under Bartoli's conditions (CH 2 Cl 2 , reflux) produced the desired homoallylic tert ‐butyl carbonate 8 in 73 % yield.…”

Lipase‐Catalyzed tert‐Butoxycarbonylation of Alcohols Using Boc2O

“…Under these conditions, however, the Boc‐protected alcohols have been frequently accompanied by the corresponding undesired symmetrical carbonates as byproducts . There have been reports on improving the methods for preparing Boc‐protected alcohols in the presence of catalysts such as CeCl 3 , V(O)(OTf) 2 , Zn(OAc) 2 , BiCl 3 , NaLaTiO 4 , mesoporous silica‐supported Er(III), MgO‐ZrO 2 nanoparticles, o ‐Py 4 Sn, and reduced graphene oxide, as well as by a catalyst‐free microwave‐assisted approach . Although these methods are useful under limited conditions, the production of Boc protected alcohols is still dependent on the alcohol structures.…”