A direct dehydrative coupling of terminal alkynes with allylic alcohols catalyzed by Pd(PPh3)4 with an N,P-ligand assisted by Ti(OiPr)4 has been developed. The coupling reaction tolerates various functional groups, providing a valuable synthetic tool to access 1,4-enynes.

Genetic activation of the bacterial two component signal transduction system, CpxRA, abolishes the virulence of a number of pathogens in human and murine infection models. Recently, 2,3,4,9tetrahydro-1H-carbazol-1-amines were shown to activate the CpxRA system by inhibiting the phosphatase activity of CpxA. Herein we report the initial structure-activity relationships of this scaffold by focusing on three approaches 1) A-ring substitution, 2) B-ring deconstruction to provide N-arylated amino acid derivatives and 3) C-ring elimination to give 2-ethylamino substituted indoles. These studies demonstrate that the A-ring is amenable to functionalization and provides a promising avenue for continued optimization of this chemotype. Further investigations *

The acyldepsipeptide (ADEP) antibiotics operate through a clinically unexploited mechanism of action and thus have attracted attention from several antibacterial development groups. The ADEP scaffold is synthetically tractable, and deep-seated modifications have produced extremely potent antibacterial leads against Gram-positive pathogens. Although newly identified ADEP analogs demonstrate remarkable antibacterial activity against bacterial isolates and in mouse models of bacterial infections, stability issues pertaining to the depsipeptide core remain. To date, no study has been reported on the natural ADEP scaffold that evaluates the sole importance of the macrocyclic linkage on target engagement, molecular conformation, and bioactivity. To address this gap in ADEP structure-activity relationships, we synthesized three ADEP analogs that only differ in the linkage motif (i.e., ester, amide, and -methyl amide) and provide a side-by-side comparison of conformational behavior and biological activity. We demonstrate that while replacement of the naturally occurring ester linkage with a secondary amide maintains biochemical activity, this simple substitution results in a significant drop in whole-cell activity. This study provides direct evidence that ester to amide linkage substitution is unlikely to provide a reasonable solution for ADEP instability.

Rational design of coplanar NDI-based conjugated molecules was achieved by covalently connecting naphthalene diimide (NDI) units with aryl (Ar) groups through vinylene (V) linkers via Heck-Mizoroki reaction. Two series of products, diolefination products (ArVNDIVAr) and hydroxylated and mono-olefination products (HONDIVAr), can be obtained, respectively, in moderate to excellent yields (45-90%) under controlled conditions, in which catalyst and base play the key roles. Density functional theory calculation discloses the outstanding planarity of the two types of products. Large bathochromic shifts are observed in both the absorbance and photoluminescence spectra of the HONDIVAr (144 and 229 nm) and ArVNDIVAr (180 and 242 nm) π-systems. Bathochromic shifts can be adjusted within the broad wavelength range by introducing 4'-substituents, either electron-withdrawing group (NO) or electron-donating group (NMe), in the phenyl group of aryl ethylenes. ArVNDIVArs show bigger bathochromic shifts than HONDIVArs.

A metal-free cascade reaction of aryl alkynoates with five different types of radical precursors (R-H) through an yne-addition/1,4-aryl migration/decarboxylation process was reported, which allowed facile and convenient access to functionalized vinyl products with "R" and protons located at the identical carbon of the formed double bond.

Direct alkynylation of Morita-Baylis-Hillman carbonates with (triisopropylsilyl)acetylene catalyzed by a Pd(OAc)2-NHC complex was developed "on water" to give the corresponding 1,4-enynes. The significant effects of water amount in the solvent on further transformations of 1,4-enynes were investigated.

Pd‐catalyzed coupling of Morita—Baylis—Hillman carbonates with (triisopropylsilyl)acetylene (II) produces 1,4‐enynes in good yields.

Unprecedented radical cascade reaction of alkynoates with various ethers (II), amides (VI), benzylic compounds (Xa,b), cycloalkanes (Xc‐e), and silane (Xf) is reported.