Reductive Cleavage of Aryl O-Carbamates to Phenols by the Schwartz Reagent. Expedient Link to the Directed Ortho Metalation Strategy

Abstract

A general, mild, and efficient method for the reductive cleavage of aryl O-carbamates to phenols, 1 → 2 using the Schwartz reagent is reported. The method is selective, tolerating a large number of functional groups; may be carried out by direct or by an economical in situ procedure; and, notably, establishes a synthetic connection to the directed ortho metalation strategy (Figure 1 ) allowing new entries into difficult to prepare contiguously substituted aromatics and heteroaromatics.

A method for increasing the solubility of industrial azo pigments for 13C and 1H NMR spectra and the assignments of their 13C and 1H NMR peaks

“…The value for C‐2 is at δ C 169.5 for Sudan 1 and at δ C 153.2 for 2‐naphthol. [ 20 ] This also agrees with the single‐crystal X‐ray diffraction studies and indicates that the pigment is in the keto‐hydrazo form, [ 21 ] which is structurally different from 2‐naphthol.…”

Transition-metal-free Baeyer–Villiger oxidation of benzaldehydes to phenols using Na2S2O8

“…2-Chlorophenol (2u). 21 Colourless liquid, 1 H NMR (400 MHz, CDCl 3 ) δ 7.31 (dd, J = 8.0, 1.5 Hz, 1H), 7.17 (td, J = 8.2, 1.5 Hz, 1H), 7.01 (dd, J = 8.2, 1.5 Hz, 1H), 6.86 (td, J = 7.9, 1.5 Hz, 1H), 5.55 (s, 1H). MS: [M] + found 128.…”

The Directed Ortho Metallation (DoM)–Cross‐Coupling Nexus. Synthetic Methodology for the Formation of Aryl–Aryl and Aryl–Heteroatom–Aryl Bonds

“…The conceptual elements 49 and [79]. For a new method using the Schwartz reagent, see [80]. Oxidative complications in direct electrophilic aromatic substitution reaction to obtain 55 render the present route of potential synthetic value for polysubstituted thiophenols.…”