Alcohols copper-catalyzed coupling

Allyl vinyl ethers may be prepared via stereospecific copper-catalyzed coupling of allyl alcohols and vinyl halides. For example, the copper catalyst derived from the tetramethyl 1,10-phenanthroline ligand shown below facilitates C-0 bond formation between ( )-vinyl iodides and allyl alcohols when the reaction mixture is heated in the presence of air. ... 

Although thiols are generally stronger nucleophiles than alcohols and amines, the sensitivity of sulfides towards oxidation as well as the formation of disulfide made the cross-coupling between aryl halides and thiols difficult. From all previously reported results, it was foimd that only aryl iodides were suitable for this copper-catalyzed coupling process. 

Copper-Catalyzed Coupling of Aryl Halides with Alcohols and Thiols... 

SCHEME 2.76 Copper-catalyzed coupling of vinyl iodides with alcohols in air [105]. 

SCHEME 2.79 Copper-catalyzed coupling of vinylboronates with aUylic alcohols [109]. 

Copper-catalyzed Suzuki cross-coupling reactions using mixed nanocluster catalysts have been studied recently. Copper-based catalysts were shown to be effective as reagents that can present an inexpensive and environmentally friendly alternative to noble metal catalysts. In the hydrogenation of cinnamic acid to corresponding alcohol, the selectivity can be varied by doping Sn with Rh colloid catalysts. A selectivity of 86% was achieved using a colloidal Rh/Sn (Rh/Sn = 1.5 1) catalyst on... 

Examples of the transition metal catalyzed formation of carbon-heteroatom bonds other than carbon-nitrogen are less abundant. In a recent survey of the copper catalyzed carbon-oxygen bond formation between alcohols and organotrifluroborates the coupling of 3-thienyltrifluoroborate and 2-furfuryl alcohol gave the expected thienyl-furfuryl-ether in good yield (6.83.),113... 

We protect one hydroxyl terminus of the commercially available 1,8-octane diol 1 by reaction with dihydropyran to give the monoalcohol, 8-tetrahydropyranyloxyoctanol 2. The protected alcohol 2 is oxidized to the aldehyde with pyridinium chlorochromate to give 8-tetrahydropyranyl-oxyoctanal 3. 1-Heptyne 4 is coupled with propargyl bromide 5 in a copper catalyzed reaction to produce the diacetylenic 1,4-decadiyne 6. 

Table 9.11 Copper/ligand catalyzed coupling of atyl halides and aliphatic alcohols.

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