A convenient gold(III)-catalyzed synthesis of azepines from the intermolecular annulation of propargyl esters and alpha,beta-unsaturated imines is reported (19 examples, 55-95% yield). This formal [4 + 3]-cycloaddition reaction is proposed to proceed via a stepwise process involving intramolecular trapping of an allyl-gold intermediate.

A β,β-sp(3)-hybridized subphthalocyanine analogue, dibenzosubtriazachlorin, was synthesized, and its significantly split Q band absorptions in longer and shorter wavelength regions relative to those of subphthalocyanines were revealed. The effect of benzo-annulation to a subtriazachlorin structure on the position of the split Q bands as well as the electronic structures was also investigated.

A denitrogenative annulation reaction of 1,2,3-benzotriazin-4(3H)-ones with allenes catalyzed by a nickel-phosphine complex to produce a variety of substituted 3,4-dihydroisoquinolin-1(2H)-ones in a regioselective manner is described. A highly enantioselective version, as well as structural evidence for the mechanistic course of this reaction, is also presented.

A sequence of Sonogashira coupling, Pd(II)-catalyzed carbonylative annulation, and benzofuran reduction (Mg, MeOH, NH(4)Cl) provides a convergent and modular synthetic route to trans-2-aryl-2,3-dihydrobenzo[b]furan-3-carboxylates, which are a structural feature of numerous biologically active natural products. This versatile strategy was applied to the formal total synthesis of the anti-HIV nat...

NHC-catalyzed annulation of enals with 2-enoylpyridines or 2-enoylpyridine N-oxides leading to the diastereoselective synthesis of β-lactone-fused cyclopentanes is reported. The reaction proceeds via the generation of homoenolate equivalent intermediates and tolerates a broad range of functional groups.

We have developed a multifunctional thiourea-phosphine catalyzed asymmetric [3 + 2] annulation of Morita-Baylis-Hillman (MBH) carbonates with maleimides, which can efficiently construct functionalized cyclopentenes bearing three contiguous stereocenters in moderate to excellent yields and excellent diastereo- and enantioselectivities. A plausible mechanism has been also proposed on the basis of...

A highly diastereoselective annulation of simple aldehydes and 5-alkenyl thiazolones, via oxidative NHC catalysis has been developed. This strategy provides facile access to a diverse library of functionalized chiral thiazolo pyrones. Aerobic oxygen can also be applied as a secondary oxidant to avoid the use of stoichiometric organic or inorganic oxidants.

The intramolecular cyclohexadienone annulation of chromium carbene complexes is examined as a method to provide general access to the Phomactin family of natural products. The importance of the stereochemistry of the carbene complex and the number of carbons in the tether connecting the carbene complex and the alkyne are probed. Additionally, the degree of the 1,4-asymmetric induction is examined.

An enantioselective strategy for the synthesis of tetracyclic motif 5, representing the northern fragment of norzoanthamine, is presented. Key to the strategy is the use of two asymmetric Robinson annulation reactions that produce the tricyclic ABC ring system with excellent stereoselectivity. Further functionalization at the periphery of the C ring produces compound 5 containing six contiguous...

This paper describes an unexpected and novel nucleophilic phosphine-catalyzed annulation of ethyl (arylimino)acetates to give polysubstituted oxoimidazolidine derivatives in moderate to good yields from simple and easily available starting materials under mild conditions. In this reaction, the addition of methyl vinyl ketone (MVK) is essential to induce the formation of oxoimidazolidines.