A series of chiral triazolium salts have been synthesized from methyl l-phenylalaninate hydrochloride. The NHCs derived from this class of novel triazolium salts were found to be highly efficient catalysts in the annulation reaction of enals and 2-naphthols. These reactions proceeded with high chemoselectivity and wide substrate scope affording enantioenriched β-arylsplitomicins in good yields ...

The first enantioselective [3 + 2] annulation of α-substituted allenoates with β,γ-unsaturated N-sulfonylimines is described. In the presence of a dipeptide phosphine catalyst, a wide range of highly functionalized cyclopentenes bearing an all-carbon quaternary center were obtained in moderate to good yields and with good to excellent enantioselectivities.

The development of an organocatalytic one-pot cascade for the annulation of simple starting materials: α,β-unsaturated aldehydes, hydrogen peroxide, β-carbonyl compounds and NBS to furnish optically active 3-pyrones in good yield and with excellent enantioselectivity is presented. Further diversification of the obtained products is demonstrated by selective reductive transformations.

Phosphine-catalyzed [2 + 4] annulation of allenoates with thiazolone-derived alkenes has been achieved under mild conditions, giving biologically important 6,7-dihydro-5H-pyrano[2,3-d]thiazole derivatives in high to excellent yields. With the use of Kwon's phosphine as the chiral catalyst, optically active products were obtained in good yields with excellent enantioselectivities.

A novel synthetic approach to functionalized indolo[2,3-a]quinolizidines is developed via an N-heterocyclic carbene (NHC)-catalyzed annulation of cyclic β-enamino esters with enals . This methodology offers a pathway for quick and efficient construction of an indolo[2,3-a]quinolizidine skeleton which is a core structure of many natural products with diverse bioactivities.

Intermolecular [3 + 2] annulation of cyclopropylanilines with alkynes is realized using visible light photoredox catalysis, yielding a variety of cyclic allylic amines in fair to good yields. This method exhibits significant group tolerance particularly with heterocycles. It can also be used to prepare complex heterocycles such as fused indolines.

A highly enantio- and diastereoselective [4+1] annulation between in situ generated ammonium ylides and o-quinone methides for the synthesis of a variety of 2,3-dihydrobenzofurans has been developed. The key factors controlling the reactivity and stereoselectivity were systematically investigated by experimental and computational means and the energy profiles obtained provide a deeper insight i...

The tandem hydroamination-annulation reaction of 4-pentyne-nitriles in the presence of amine nucleophiles and a cooperatively operating catalyst system, consisting of Ph(3)PAuCl and Zn(ClO(4))(2), provides an efficient route to 2-aminopyrroles. Two regioisomeric 2-aminopyrroles were formed in moderate to good yields.

The KO(t)Bu-mediated annulation of acetonitrile with aldehyde was observed, in which the cleavage of four C(sp(3))-H bonds occurred and a total of eight new bonds were formed during the synthesis of substituted dihydropyridinones in the presence of peroxide. Furthermore, dihydropyridinones have been transformed into pyridinones using KO(t)Bu in DMSO.

2-Azidoacrylates undergo [4+3] annulation with phthalides under anionic conditions at low temperatures to furnish 5-hydroxy-2-benzazepinones, the formation of which represents a new concept for the construction of azepines as well as a new reactivity of 2-azidoacrylates.