Propynylated aromatic

The low yields of the Mori dimerization presented a challenge for the utilization of the simple catalyst systems [12] optimization by increasing the reaction temperature from 105 to 130-150 °C combined with the slow introduction of N2 into the reaction mixture increased the isolated yield of 8 from 52 % to 82 % (Scheme 7). If the propynylated aromatics (13, 14)... 

Alkenyl(phenyl)iodine(III) compounds can also serve as starting materials in rearrangements. Allenyl(aryl)iodine(III) compounds of type 86 can be synthesized from (diacetoxyiodo) derivatives 85 and propargylsilanes [145]. It depends on the leaving group ability of the aromatic substituent on iodine in 86 as to whether the reaction proceeds via nucleophilic substitution to compounds of type 87 or by an iodonio-Claisen rearrangement to compounds 88, Scheme 37 [146,147]. The easy access to propynyl compounds 87 has been shown [148] and solvent effects in these reactions have been investigated as well [149,150]. 

Mullen and coworkers utilized the Diels-Alder reaction to prepare hb-PPs (hb-P25 to hb-P27) with Mw up to 107000 from ethynyl-, propynyl-, and phenylethynyl-substituted tetraphenylcyclopentadienones (Scheme 13) [47]. Despite their high molecular weights and rigid phenyl rings, all the polymers showed good solubility in common aromatic solvents such as toluene and benzene. 

An extension of this work has resulted in the synthesis of related 6,6-disubsti-tuted (bipyridyl) ligand derivatives containing pyromellitimide spacers connected with propynyl, butynyl and propynyloxy linkers.The first of these ligands was shown to yield a chiral di-zinc(II) cationic complex of type [Zn2L2] . This species is stabilised by the presence of an aromatic guest p- or o-dimethoxybenzene) in its cavity. Related dinuclear species were also shown to form with cadmium(II) and nickel(II). 

From a further observation that the 3-methylene analogues (35) and (36) of 10) -difluoromethyl- and 10/S-(2-propynyl)estr-4-ene-3,17-dione, both known to be irreversible inhibitors of AR [168, 169], were inactive, it was concluded that the 3-keto function was required to assist in the primary oxidation of the 10-methyl group of these inhibitors. This conclusion indicates a possible enzyme guided movement of the primary oxidation products to realign for the 2-oxidation leading to eventual aromatization, assuming this pathway is being evoked. This is consistent with the observation that the... 

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