Heteroaromatic carboxylic acids have been directly coupled with imines using propylphosphonic anhydride (T3P) and NEt(iPr)₂ to form azaspirocycles via intermediate N-acyliminium ions. Spirocyclic indolenines (3H-indoles), azaindolenines, 2H-pyrroles and 3H-pyrroles were all accessed using this metal-free approach. The reactions typically proceed with high diastereoselectivity and 3D shape analysis confirms that the products formed occupy areas of chemical space that are under-represented in existing drugs and high throughput screening libraries.

Indolyl α-diazocarbonyls can be selectively cyclized to give six distinct products through the careful choice of catalyst and reaction conditions. A range of catalysts were used, including complexes of Rh^II, Pd^II, and Cu^II, as well as SiO₂, to promote diazo decomposition and subsequent cyclization/rearrangement through a range of mechanistic pathways.

Indolyl α-diazocarbonyls can be selectively cyclized to give six distinct products through the careful choice of catalyst and reaction conditions. A range of catalysts were used, including complexes of Rh^II, Pd^II, and Cu^II, as well as SiO₂, to promote diazo decomposition and subsequent cyclization/rearrangement through a range of mechanistic pathways.

Medicinally relevant spirocyclic indolenines, carbazoles and quinolines can each be directly synthesised selectively from common indolyl ynone starting materials by catalyst variation. The high yielding, divergent reactions all proceed by an initial dearomatising spirocyclisation reaction to generate an intermediate vinyl–metal species, which then rearranges selectively by careful choice of catalyst and reaction conditions.

A facile copper(II)-mediated C–H bond oxidation and C–C bond formation procedure has been applied to the synthesis of indole derivatives. Intramolecular oxidative coupling of 3,3-disubstituted enamines proceeded using a non-expensive and air-stable copper salt, Cu(2-ethylhexanoate)₂, to afford the corresponding C-3 quaternary indolenine products in good to excellent yields. 1H-Indoles can be prepared in a similar manner but in this case, Cu(OAc)₂·H₂O has been found to be the preferred oxidant.

A high-yielding silver(I)- or copper(II)-catalyzed dearomatizing spirocyclization strategy allows the conversion of simple aromatic compounds that contain ynone substituents, including indole, anisole, pyrrole, and benzofuran derivatives, into functionalized spirocyclic scaffolds. A high-yielding asymmetric variant furnishes spirocyclic indolenines in up to 89:11 e.r.

A high-yielding silver(I)- or copper(II)-catalyzed dearomatizing spirocyclization strategy allows the conversion of simple aromatic compounds that contain ynone substituents, including indole, anisole, pyrrole, and benzofuran derivatives, into functionalized spirocyclic scaffolds. A high-yielding asymmetric variant furnishes spirocyclic indolenines in up to 89:11 e.r.

The first total synthesis of phacelocarpus 2-pyrone A is reported. The original natural compound was tentatively assigned (by NMR spectroscopy) as containing two cis-alkenes and a trans-vinyl ether connected to a 2-pyrone ring motif. Our computational predictions indicated that a cis-vinyl ether motif was equally feasible. Attempts to prepare the trans-vinyl ether were met with no success. The all cis-target compound was synthesised in nine steps, employing key regio- and stereoselective reactions including Au^I-catalysed vinyl etherification, Wittig alkenylation and end-game Stille macrocyclisation. Analysis of the NMR data enabled identification and confirmation of the correct structure of phacelocarpus 2-pyrone A, containing a cis-vinyl ether. Our studies pave the way for future development of methodologies to these structurally distinct pyrone skipped-polyenyne natural products.

A copper(II)-catalysed approach to oxindoles, thio-oxindoles, 3,4-dihydro-1H-quinolin-2-ones, and 1,2,3,4-tetrahydroquinolines via formal CH, ArH coupling is described. In a new variant, copper(II) 2-ethylhexanoate has been identified as an inexpensive and efficient catalyst for this transformation, which utilises atmospheric oxygen as the re-oxidant.

This review describes transition-metal-catalysed and -mediated processes for the preparation of oxindoles from anilides through C(3)–C(3a) bond formation. Traditional methods, such as the Heck reaction, and recent developments, including direct Ar–H coupling processes, are presented, as are applications in natural product synthesis.