A concise total synthesis of citreofuran 4 is described, a structurally unique octaketide derivative belonging to the curvularin family. Key steps involve elaboration orsellinic acid methyl ester 5 14, which converts, on attempted formation corresponding chloride, 3-alkoxyisocoumarin 20. This heterocycle can be used as an activated give ketone 21 treatment with 3-pentynylmagnesium bromide in presence TMSCl activating agent. Ring- closing alkyne metathesis (RCAM) diyne catalyzed by...

Abstract The Suzuki coupling reaction between alkynylboronic esters (generated in situ from acetylenic derivatives) and aryl bromides, pyridyl bromides or vinyl is reported. 5‐ endo ‐ dig ‐iodocyclisation of o ‐alkynylanisoles, generated by this palladium‐catalyzed reaction, was performed with N ‐iodosuccinimide (NIS) the presence BCl 3 . 2‐Substituted 3‐iodobenzo[ b ]furans were synthesized transformed into 2,3‐disubstituted benzo[ reactions high yields. (© Wiley‐VCH Verlag GmbH & Co....

By treatment with s-BuLi/TMEDA at −78 °C, unprotected 2-methoxybenzoic acid is deprotonated exclusively in the position ortho to carboxylate. A reversal of regioselectivity observed when treated n-BuLi/t-BuOK. These results are general utility for one-pot preparation a variety very simple 3- and 6-substituted acids that not easily accessible by conventional means. The potential usefulness method demonstrated expedient synthesis lunularic acid.

Abstract Efficiency of ionic liquid supported organotin reagents in Stille cross‐coupling reactions involving aryl bromides has been investigated. In a general manner, products were isolated with good yields by using very simple catalytic system without the need solvent, ligand, or additives. The compounds recycled loss activity and contamination tin was limited controlled ([Sn] < 3 ppm).

A new effective Suzuki-Miyaura coupling reaction between alkynylboronic esters (generated in situ from acetylenic derivatives) and arylbromides or vinylbromides is reported.

A study concerning the mechanism of LDA-mediated ortho and remote metalation N,N-dialkyl-2-biphenyl carboxamides (e.g., 4a) is reported. On basis site-selective lithiation/electrophile quench experiments, including deuteration, LDA 4 proposed to involve initial amide-base complexation (CIPE) equilibrium formation 5, whose fast reaction with an in situ electrophile (TMSCl) afford 6 prevents its equilibration 7. In absence electrophile, 5 undergoes via 4a 7, fate instantaneous cyclization a...

New general methodology of value in aromatic chemistry based on ortho-metalation sites o-, m-, and p-anisic acids (1-3) (Scheme 1) is described. The metalation can be selectively directed to either the ortho positions by varying base, temperature, exposure times. Metalation o-anisic acid (1) with s-BuLi/TMEDA THF at -78 degrees C occurs exclusively position adjacente carboxylate. On other hand, a reversal regioselectivity observed n-BuLi/t-BuOK. With LTMP 0 C, two directors m-anisic (2)...

The X–H insertion reaction constitutes a powerful tool to create diversity through the diazo decomposition of diazocarbonyl compounds. However, until now, on α-diazo-β-aryl-β-hydroxyester scaffolds, readily prepared by aldol-type addition, remained challenge for organic chemist. We report herein first O–H insertions O-protected α-diazo-β-aryl-β-hydroxyesters, providing straightforward access wide range α,β-dioxygenated esters modulation alcohol and aryl substituent. key feature achieving...

Significant research endeavors have been devoted to developing adhesives with reversible switching capabilities, allowing them activate adhesion in response diverse environmental stimuli. Among these, photo-switchable stand out as particularly promising. The presence of a photo-reversible solid-to-liquid transition, characterized by transition temperature (TSL), certain azobenzene-containing polymers offers compelling avenue for creating such adhesives. development method based on Atomic...

[reaction: see text] Exposing 2-fluorobenzoic acid (1a) to 2.2 equiv of LTMP at ca. -78 degrees C leads deprotonation the 3-position whereas 2-chloro/bromobenzoic acids (1b,c) are lithiated adjacent carboxylate. The resulting dianions 3Li-1a and 6Li-1b,c trapped as such by chlorotrimethylsilane. In absence internal quench, isomerize more stable 3Li-1b,c. latter eliminate lithium halide set free benzyne-3-carboxylate (2) that reacts regioselectively with give 3-tetramethylpiperidinobenzoic (3).

If employed in THF at 0 °C, LTMP metalates meta-anisic acid the doubly activated position. In contrast, n-BuLi/t-BuOK deprotonates position C-4 preferentially low temperature. Functionalization C-6 requires protection of C-2 site beforehand. As a result these findings, new mechanism is proposed for heteroatom-directed ortholithiation aromatic compounds.

The mechanism of the metalation 2-biphenyl carboxylic acid (1) with Lochmann−Schlosser superbase was determined by deuteriolysis. Both ortho (C3) and remote (C2') positions are metalated. C2'-metalated species 2 cyclizes instantaneously. Under suitable conditions, doubly charged geminal dimetallo dialkoxide group C(OM)2 4 directs in adjacent position (C1), affording a stable 1-metallo-9H-fluorene-9,9-dimetallo 5 that can be trapped diverse electrophiles to give 1-substituted...

Abstract Unprotected biphenyl‐2‐carboxylic acid can be cleanly metalated with sec ‐butyllithium at the position adjacent to carboxylate and then subjected site‐selective electrophilic substitution. The remote C2′‐position is attacked by superbasic mixture of n potassium tert ‐butoxide (LICKOR, 3.5 equiv.) in THF or benzene 20–60 °C. resulting dianion cyclizes give fluorenone skeleton. metalation reactions biphenyl‐3‐ ‐4‐carboxylic acids are also described. (© Wiley‐VCH Verlag GmbH & Co....

Substitution of an ortho-fluoro or methoxy group in 1- and 2-naphthoic acids furnishing substituted naphthoic occurs good to excellent yields upon reaction with alkyl/vinyl/aryl organolithium Grignard reagents, the absence a metal catalyst without need protect carboxyl (CO(2)H) group. This novel nucleophilic aromatic substitution is presumed proceed via precoordination organometallic substrate, followed by addition/elimination.

This work describes an integrated approach for designing on demand Self-Assembled Monolayers (SAMs) silicon oxides and particularly glass substrates cell biology applications. Starting from commercially available compounds, the strategy relies thiol–ene reaction provides high quality SAMs exhibiting adhesive anti-adhesive patterns.

[reaction: see text] By treatment with s-BuLi, s-BuLi/TMEDA, or t-BuLi at approximately -78 degrees C, 4-fluoro- and 4-chlorobenzoic acids (1a,b) are metalated preferentially in the position adjacent to carboxylate. A complete reversal regioselectivity is observed for 1a when treated LTMP; a sequential process involving rapid intraaggregate lithiation through quasi dianion complex "QUADAC" postulated explain unusual reactivity of Me(2)S(2) I(2).

Substitution of the fluoro or methoxy group in unprotected 2-fluoro- and 2-methoxybenzoic acids to afford N-aryl N-alkyl anthranilic occurs upon reaction with lithioamides under mild conditions absence a metal catalyst.

A new class of chiral 1,2-amino ether ligands, readily accessible from naturally occurring α-amino- or α-hydroxy acids, was found to provide high levels both conversion and stereocontrol (up 95:5 er) in intramolecular carbolithiation reactions, outperforming the benchmark ligand (-)-sparteine. The could be used a substoichiometric amount (0.25 equiv) without significant loss enantioselectivity.

Whereas standard strong bases (n-BuLi, s-BuLi/TMEDA, n-BuLi/t-BuOK, TMPMgCl·LiCl, and LDA) reduce the N═N bond of parent azobenzene (Y = H), aromatic H→Li permutation occurs with LTMP when a suitable director lithiation OMe, CONEt2, F) is present in benzene residue azo compound. The method allows direct access to new substituted azobenzenes.