Intramolecular oxidative coupling of diphenolic, monophenolic, and nonphenolic substrates

Development and Application of New Oxidation Systems Utilizing Oxometalate Catalysts

“…[112][113][114][115][116][117][118] Many attempts to make spirodienones in vitro have been achieved by oxidative phenolic coupling reaction using heavy metal oxidizing reagents such as vanadium(V), iron(III), manganese(IV), or thallium(III) salts, but unsatisfactory results were encountered in many cases. [119][120][121][122][123][124][125][126][127][128][129][130][131] Alternatively, phenolic coupling reactions using hypervalent iodine(III) reagents could also lead to spirodienones from para-substituted phenols 79,82,[132][133][134][135][136] ; however, phenolic instability often causes difficulties in smooth conversions. Therefore the development of effective routes to spirodienones remains an important topic in organic synthesis.…”

Oxidative Coupling of Phenols and Phenol Ethers

“…Anodic oxidation was used to prepare homoglaucine (83) from homolaudanosine (82; 34%).68 Thallium trifluoroacetate has proved an excellent reagent for similar oxidations, e.g. Thus (±)-steganacin was synthesized 71 using intracoupling of the malonate-derived bisaryl butane (94) to (95) OMe (89) OMe (90) Reduction of the methoxycarbonyl function and Simmons-Smith methylation then generated the cyclopropane (90; R = CH20H) from which (±)-steganone (91) could be generated via ring expansion with the correct biaryl twist, relative to lactone fusion.…”

Total Synthesis of Bisbibenzyl Dibenzofuran Asterelin A via Intramolecular Oxidative Coupling

“…Ultimately, it was found that VOCl 3 was the most effective oxidant for the construction of dibenzofuran. The oxidation of 18 with VOCl 3 in CH 2 Cl 2 at 20°C provided 18 in 58% yield [12]. Finally, the total synthesis of asterelin A (1) was accomplished by treating 18 with BBr 3 .…”