Iodo palladium coupling with

Deoxyvariolin B 149 has been synthesized by a palladium-catalyzed cross-coupling reaction of iodo derivative 147 with tin compound 148 (Equation 5) <2001TL315, 2003JQC10020, 2003TL6191, 2004JOC4974>. 

Palladium-catalyzed reactions of arylboronic acids have been utilized to craft precursors for constructing indole rings. Suzuki found that tris(2-ethoxyethenyl)borane (149) and catechol-derived boranes 150 readily couple with o-iodoanilines to yield 151, which easily cyclize to indoles 152 with acid [158]. Kumar and co-workers used this method to prepare 5-(4-pyridinyl)-7-azaindoles from 6-amino-5-iodo-2-methyl-3,4 -bipyridyl [159], A similar scheme with catechol-vinyl sulfide boranes also leads to indoles [160]. A Suzuki protocol has been employed by Sun and co-workers to synthesize a series of 6-aryloxindoles [161]. 

Various intermolecular coupling reactions involving acetylene hydrocarbons have been reported to lead to vinylallenes. For example, 1-phenylpropyne (93), after activation with Hg(II) chloride, is first metalated by butyllithium treatment, then trans-metalated with zinc bromide and finally coupled with 1-iodo-l-phenylethene (94) in the presence of tetrakis(triphenylphosphine)palladium to provide the diphenylvinyl-allene 95 in moderate yield (Scheme 5.12) [31]. 

The iodo benzamide derivative of pyrrolo[2,l-c][l,4]benzodiazepine 367 (R = I, Scheme 75, Section 5.1.1) reacts with bis(tributyl)tin, lithium chloride and tetrakis(triphenylphosphine) palladium(O) in refluxing dioxane to yield the stannyl derivative 370. The latter couples with substituted aryl bromides in the presence of... 

Hydroboration of the alkyne 252 with catechol borane 235 is regioselective for steric reasons and the resulting -vinyl boronate 253 couples with the iodo-benzene 254 under palladium catalysis. 

Because 3-chloropyridazines were not found to be very reactive in palladium coupling reactions and the bromo and iodo analogues are not readily available, the preparation and use of triflate esters of pyridazines have been developed. The readily prepared triflates undergo coupling with terminal acetylenes in the presence of palladium and copper iodide (Equation (27)). Reactions are rapid, normally complete in 0.5 to 6 hours at room temperature, and yields are high. In a comparative experiment 3-chloro-4-methyl-6-phenylpyridazine with 3,3-dimethyl-3-hydroxy-l-propyne gave only a 33% yield of 3-(3,3-dimethyl-3-hydroxy-l-propynyl)-4-methyl-6-phenylpyridazine after 12... 

Further investigations into the palladium(ll)-catalysed cross-couphng of olefins with iodopyrimidines have been published. As previously reported,2-iodo-4,6-dimethylpyrimidine and its 4-iodo-2,6-dimethyl isomer do not couple with ethyl acrylate if a reagent mixture of Pd(OAc)2, PhaP, and EtaN is used however, omission of the triphenylphosphine permits the coupling to proceed in reasonable yields. Palladium black can also be used as the catalyst. ... 

Preparation of the lactone fragment started with a mixture of (2 ,45) and (25,4S)-4-methyl-2-phenylsulfenyl-y-butyrolactone (53) which was alkylated with ( )-l,9-diiodo-l-nonene. The corresponding iodo compound 100 so obtained was then coupled with the alkyne 99 through the efficient palladium catalyzed reaction (Pd(PPh3)4, Cul, Et3N, room temperature) in 86 % yield. Enyne reduction of 101 with Wilkinson s catalyst, then oxidation of the sulfide into sulfoxide and subsequent thermal elimination gave rise to the title compound 90. The synthesis was achieved in 20 steps and in 0.36 % yield. 

A number of syntheses of di- and polyacetylenes has been reported. 1-Iodo-l-alkynes couple with terminal acetylenes under palladium-copper catalysis to give 1,3-diynes thus y-iodopropargyl alcohol and phenylacetylene afford compound 30. Oxidative coupling of 1 -alkynes to yield symmetrical 1,3-diynes is brought about by air and copper(I) chloride in the presence of N, A -tetramethylethylenediamine (equation Trialkylsilyl sub-... 

The 2-bromododeca-l,ll-dien-6-yne derivative 461 undergoes a triple cyclization, followed by rearrangement, under the influence of a palladium catalyst to yield 462. Cross-coupling of the iodo compound 463 with ( )-l-hexen-l-ylzinc chloride in the presence of tetrakis(triphenylphosphine)palladium yields 68% of the indane 464 and 19% of the uncyclized product 465 ". ... 

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