12 Benzoxazoles
Glorius et al. reported a Cu-catalyzed domino C–N and C–O bond formation
to elaborate benzoxazoles from dihalobenzenes and amides (Scheme 59) [101].
1,2-Diiodobenzenes and 1,2-dibromobenzenes displayed well for this process.
Differently substituted benzoxazoles could regioselectively be formed from the
corresponding 1-bromo-2-chlorobenzenes. The amidation occurred selectively at
the C–Br position and then C–O bond formation took place at the C–Cl moiety.
No product was isolated when 1,2-dichlorobenzene was used, indicating that
chloride was only reactive for the intramolecular cyclization step.
13 Quinazolinones and Related Heterocycles
CuI-catalyzed coupling of amidine hydrochloride salts 172 with 2-halobenzoic
acid and subsequent condensative cyclization worked well to provide 2-substituted
quinazolinones 173 at room temperature (Scheme 60) [102, 103]. The orthosubstituent effect directed by the carboxylic acid group should be the reason of
Scheme 58 Carbazole synthesis via a Pd-catalyzed domino amination/C–H bond activation process
Scheme 59 CuI-catalyzed synthesis of benzoxazoles from dihalobenzenes and amides
Scheme 57 Total synthesis of murrastifoline-A via Pd-catalyzed double N-arylation
110
Y. Jiang and D. Ma
Glorius et al. reported a Cu-catalyzed domino C–N and C–O bond formation
to elaborate benzoxazoles from dihalobenzenes and amides (Scheme 59) [101].
1,2-Diiodobenzenes and 1,2-dibromobenzenes displayed well for this process.
Differently substituted benzoxazoles could regioselectively be formed from the
corresponding 1-bromo-2-chlorobenzenes. The amidation occurred selectively at
the C–Br position and then C–O bond formation took place at the C–Cl moiety.
No product was isolated when 1,2-dichlorobenzene was used, indicating that
chloride was only reactive for the intramolecular cyclization step.
13 Quinazolinones and Related Heterocycles
CuI-catalyzed coupling of amidine hydrochloride salts 172 with 2-halobenzoic
acid and subsequent condensative cyclization worked well to provide 2-substituted
quinazolinones 173 at room temperature (Scheme 60) [102, 103]. The orthosubstituent effect directed by the carboxylic acid group should be the reason of
Scheme 58 Carbazole synthesis via a Pd-catalyzed domino amination/C–H bond activation process
Scheme 59 CuI-catalyzed synthesis of benzoxazoles from dihalobenzenes and amides
Scheme 57 Total synthesis of murrastifoline-A via Pd-catalyzed double N-arylation
110
Y. Jiang and D. Ma