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A straightforward N-heterocyclic carbene (NHC)/LiCl-mediated synthesis of dihydropyranones from α,β-unsaturated carboxylic acids and 1,3-dicarbonyl compounds was realized through the in situ activation strategy. The key advantages of this protocol include ready availability and high stability of starting materials, good yields, and excellent enantioselectivity. [ABSTRACT FROM AUTHOR]

Abstract: N-Heterocyclic carbene (NHC)-catalyzed organocascade reactions via redox processes were found to be a simple and flexible procedure for the synthesis of a series of suitably functionalized 1-substituted 4-aryl-tetrahydroquinoline-2,5-diones. A wide range of potential biologically active quinoline derivatives for biomedical screening were obtained. [Copyright &y& Elsevier]

Smooth as isatin! A straightforward synthesis of spirocyclic oxindole–dihydropyranones through an N‐heterocyclic‐carbene‐catalyzed [4+2] annulation of α‐bromo‐α,β‐unsaturated aldehydes or α,β‐dibromoaldehyde bearing γ‐H with isatin derivatives under mild reaction conditions is disclosed (see scheme). The concise construction, ready availability of the starting materials, avoidance of external oxidants, and the potential utilization value of final products in molecular biology and pharmacy makes this approach particularly attractive. [ABSTRACT FROM AUTHOR]

An efficient assembly of dihydropyranone was realized via the in situ activation of α,β ‐ unsaturated carboxylic acid and the subsequent formal [3+3] reaction with 1,3 ‐ dicarbonyl compound synergistically mediated by N ‐ heterocyclic carbene and LiCl. The ready availability and high stability of the starting materials, good yields, and excellent enantioselectivity make this protocol greatly attractive in the chemistry community. More information can be found in the Communication by Changsheng Yao et   al. on page   678 in Issue 5, 2016 (DOI: 10.1002/asia.201501353). [ABSTRACT FROM AUTHOR]

Underthe cooperative catalysis of NHC/Lewis acid, the mild, straightforward[4 + 2] annulation of α-bromo-α,β-unsaturated aldehydesbearing γ-H with isatin derivatives gave spirocyclic oxindole–dihydropyranonesstereoselectively. This approach is particularly attractive due tothe concise construction, avoidance of external oxidants, and thepotential utilization value of final products in molecular biologyand pharmacy. [ABSTRACT FROM AUTHOR]

A diagram is presented which shows the N-heterocyclic carbene-catalyzed [4 + 2] cyclization of 2-bromo-2-enal with 3-alkylenyloxindoles.

An abstract of the study "N-Heterocyclic Carbene-Triggered Transition-Metal-Free Synthesis of 2,3-Disubstituted Benzofuran Derivatives" by Y. Xie and colleagues is presented.

The reaction between various isatin derivatives and 3-aryl substituted but-2-enoic acids succeeds in high yields and with high enantiomeric excesses. [ABSTRACT FROM AUTHOR]

A NHC/Lewis acid catalyzed [4 + 2] annulation of α-bromo-α,β-unsaturated aldehydes bearing γ-H with isatin is developed to yield spirocyclic oxindole-dihydropyranones in good enantioselectivity. [ABSTRACT FROM AUTHOR]