Pd-Catalyzed Indolization/peri-C–H Annulation/N-Dealkylation Cascade to Cyclopenta-Fused Acenaphtho[1,2-b]indole Scaffold

Abstract

A novel Pd-catalyzed cascade reaction of N,N-dialkyl-substituted o-alkynylanilines involving an indolization/peri-C–H annulation/N-dealkylation sequence has been developed to construct a cyclopenta-fused acenaphtho­[1,2-b]­indole (ANI) scaffold. A variety of aromatic hydrocarbons having a peri-C–H bond at the alkynyl terminus, such as naphthalene, phenanthrene, pyrene, and fluoranthene, were employed, affording the corresponding π-extended ANI derivatives. The ANI molecules showed relatively narrow energy gaps by increasing HOMOs and lowering LUMOs, implying their potential applications as π-segments in low-band-gap materials.

Pd(II)‐Catalyzed C−H Silylation of o‐Alkynylanilines Initiated by an Aminopalladation To Access Disilylated 2‐Phenyl‐1H‐indoles

“…Based on the above results and previous work, [7,12f,17] a plausible mechanism for this protocol is depicted in Scheme 4. Initially, 1 undergoes an intramolecular aminopalladation to form indolium‐Pd(II) intermediate A through a 5‐ endo ‐ dig manner.…”

A regiodivergent Truce–Smiles rearrangement: a strategy for the synthesis of arylated indoles promoted by KN(SiMe3)2

“…On the other hand, cyclization of a metallated ortho-amino group on the alkyne forms an indolylmetal intermediate that can be trapped by external electrophiles, for example, via the Heck reaction, 60 Sonogashira reaction, 61 or Suzuki reaction, 62,63 among others (Scheme 1b). [64][65][66][67][68][69][70][71][72][73][74] In the current study (Scheme 1c), we employ 2-arylpropargyl anilines with weakly acidic benzylic sp 3 C-H bonds. Thus, base initiated deprotonation-nucleophilic attack of the sulfo-namido nitrogen on the alkynyl moiety results in cyclization and produces a reactive sp 2 -hybridized carbanion.…”

“…On the other hand, cyclization of a metallated ortho -amino group on the alkyne forms an indolylmetal intermediate that can be trapped by external electrophiles, for example, via the Heck reaction, 60 Sonogashira reaction, 61 or Suzuki reaction, 62,63 among others (Scheme 1b). 64–74…”

Construction of Alkylidene Fluorene Scaffolds Using Pd-Catalyzed Direct Arene/Alkene Coupling Strategy

“…However, no versatile methods for the synthesis of AF derivatives with extended PAH and polycyclic heteroarene (PHA) scaffolds have been reported so far. In light of the diverse synthetic utilities of AFs and our interest in the construction of highly π-extended PAHs using aromatic C–H bond functionalization, , we pursued the development of a new method for the synthesis of AFs via direct arene/alkene coupling reactions.…”