Domino Reactions Consisting of Heterocyclization and 1,2‐Migration—Redox‐Neutral and Oxidative Transition‐Metal Catalysis

Abstract

Two cats, two paths: two novel domino reactions starting from 6-hydroxy-2-alkyl-2-alkynylcyclohexanones have been discovered. While redox-neutral platinum catalysis gives rise to furans through a sequence of cyclization, 1,2-shift, and Grob fragmentation, oxidative copper catalysis provides an entry to bicyclic 2,3-dihydrofurans. Upon cyclization and oxidation, an unusual benzilic acid rearrangement can take place in this case.

Mccrearamycins A–D, Geldanamycin‐Derived Cyclopentenone Macrolactams from an Eastern Kentucky Abandoned Coal Mine Microbe

“…Consistent with the impact of CuCl 2 on benzilic acid rearrangement stereoselectivity and yield, [14] evaluation of the putative 21 benzilic acid rearrangement in the presence of transition metal salts and various other known benzilic acid rearrangement promoters revealed CoCl 2 to afford the best overall yield and stereoselectivity (Table 1). Single-crystal X-ray diffraction of the isolated product 23 further established the relative C-2/C-3 trans -configuration (Table 1 and S7, CCDC 1496415), consistent with the signature 23 2-OH to 3-CH NOE and corresponding 18-OH to 20-CH NOE of mccrearamycin A ( 7 ).…”

Transition Metal-Mediated Synthesis of Monocyclic Aromatic Heterocycles

“…A subsequent Grob-type fragmentation of 2-148 followed by a protiodemetalation leads to a formation of the furan core 2-146 bearing 4-oxobutyl group (Scheme 41). 84 …”

The Fantastic Four: A plug ‘n’ play set of optimal control pulses for enhancing NMR spectroscopy

“…A Furan with substrate 1-methoxy-4methylbenzene (4-(5-(4-methoxyphenyl)-3methylfuran-2-yl)butanal) ( Fig. 4c), synthesized by a domino reaction (see table 3, entry 2 in [38]), was used to test the HMBC pulse sequence.…”