Bicyclic Cyclopentadienes with N,S Substituents

A Three‐Dimensionally π‐Conjugated Diradical Molecular Cage

“…The synthesis started from Suzuki coupling reaction between tri(4‐iodo‐2,3,5,6‐tetrachlorophenyl)methane ( 1 ) and the 9‐ n ‐butyl‐9 H ‐carbazol‐3‐ylboronic acid ( 2 ), which gave the key intermediate 3 in 90 % yield (Scheme ). Regioselective bromination of 3 with N ‐bromosuccinimide (NBS) in chloroform gave the tribromide 4 in 77 % yield.…”

The chemistry of the carbon–transition metal double and triple bond: annual survey covering the year 2002

“…352), which rapidly cyclized to a cyclopentadiene derivative (e.g. 353) [488]. After decomplexation of tungsten to afford 354, an additional mole of enynylcarbene complex could be incorporated through a Diels-Alder reaction followed by cyclization to afford a complex ring system (e.g.…”

Regiocontrol of Annelation of Cyclopentene-1-thiones and Cyclopenten-1-ones to Alkenes with the Aid of (1-Alkynyl)carbene Complexes (M = Cr, W)

“…[12] Application of an excess of (1-alkynyl)carbene complex 1a in its reaction with phenylthiol 2b resulted in the formation of a [2ϩ2] cycloadduct 15a between the highly reactive tetrahydropentalene 14a and compound 1a. [8,13] [2ϩ2] Cycloadducts (15b and c) to the SCϭC units of tetrahydroindeneand hexahydroazulenes 14b and 14d were not obtained. If the reaction between (1-alkynyl)carbene complex 1a and compound 2b was performed in the presence of triethylamine at Ϫ20°C, it resulted in the formation of an isomer (17a) of compound 12a in 85% isolated yield.…”

“…[2] We recently reported on the formation of cyclopentadienes [3] by π-cyclization of 1-metalla-1,3,5-hexatrienes, [4,5] which were readily derived from [2-(cyclopent-1-enyl)-1-alkynyl]carbene complex 1a by addition of protic nucleophiles NuH. [6] For example, formation of cyclopentadienes could be triggered by addition of secondary amines R 2 NH, secondary phosphanes R 2 PH (R ϭ tBu, cC 6 H 11 ), [7] and oxygen nucleophiles [8] ROH (R ϭ aryl, aroyl and acyl), respectively, to (1-alkynyl)carbene complex 1a. Whilst nitrogen or phosphorus nucleophiles led to production of cyclopentadiene complexes, oxygen nucleophiles gave highly reactive, metal-free cyclopentadienes, such as 1-acyloxy-3-alkoxytetrahydropentalenes.…”

“…[8,9] Scheme 1. Cascade reaction initiated by addition of oxygen nucleophiles RCO 2 H to [2-(cyclopent-1-enyl Reaction of sulfur nucleophiles, like thioacylates RC-(ϭO)S Ϫ or thio(imino)acylates RC(ϭNH)S Ϫ , with [2-(cyclo-alk-1-enyl)-1-alkynyl]carbene complexes 1a؊c were found to afford bicyclic cyclopentadienes containing sulfur substituents.…”