INDIUM MEDIATED REDUCTIVE ACYLATIONS OF NITROARENES TOWARDSN,O-DIACYLATEDN-ARYLHYDROXYLAMINES^*

Indium in Organic Synthesis

“…Performing the indium-mediated reduction of halogensubstituted nitrobenzenes and nitropyridines in the presence of acetic acid and catalytic amounts of indium trichloride, Kim et al isolated N,O-diacylated N-arylhydroxylamines in moderate to good yields. 146 N-O-Cleavage was observed as a side reaction especially in protic solvents. Nevertheless, proton sources accelerated the reaction significantly, thus the best results were obtained us-…”

Synthesis of Indolines and Derivatives by Aza‐Heck Cyclization

“…[16] Previously,t he single-step semi-reduction of nitroarenes to N-aryl-N-hydroxy carbamates had been reported. [17] Although these products have not been explored in crosscoupling reactions,w ee nvisioned that these might make outstanding substrates,not only for their potential carbonate leaving group,b ut also for their ease of preparation. Moreover, substrate assembly would be aided by the vast chemistry of nitroarene synthesis.…”

Synthesis of Indolines and Derivatives by Aza‐Heck Cyclization

“…We focused on the easily reduced palladium precatalyst (COD)Pd(CH 2 SiMe 3 ) 2 and selected P(OCH 2 CF 3 ) 3 as the ligand, as it has shown success in previous aza-Heck reactions ( Table 1, entry 1). [17] Although these products have not been explored in crosscoupling reactions,w ee nvisioned that these might make outstanding substrates,not only for their potential carbonate leaving group,b ut also for their ease of preparation. We then sought al eaving group that might favor greater reactivity.W e speculated that ac arbonate leaving group might serve such as role,asdecarboxylation might lead to irreversible oxidative addition.…”

“…Ar ange of functional groups are compatible with this cyclization, including ethers (16,19,22), carbonyl groups (7,(11)(12)(13)20), an itrile (8), an aryl chloride (17), and various appended heterocycles (19)(20)(21)(22). Unfortunately,a ryl bromide is not tolerated (18).…”