Transition Metal-Catalyzed Carbocyclizations in Organic Synthesis

Metal-Assisted Cycloaddition Reactions in Organotransition Metal Chemistry

“…The present paper on (stoichiometric) metal-assisted cycloaddition reactions therefore deals with reactions defined under category i, and shall in due time be followed by (stoichiometric) organometal cycloadditions. Metal-catalyzed cycloaddition reactions have in the meantime been covered sufficiently by the reviews of Lautens 4 on Transition Metal-Mediated Cycloaddition Reactions and of Ojima 5 on Transition Metal-Catalyzed Carbocyclizations in Organic Synthesis. The title of the review of Lautens suggests considerable overlap with the present article.…”

“…Naturally, such interference does not apply to benzylidene transfer reactions which can efficiently and stereoselectively be effected with (CO) 5 WdCH-C 6 H 4 R [17][18][19] or Cp(CO)(L)MdCH(C 6 H 4 R) + (M ) Fe, Ru; L ) CO, PPh 3 ; R ) p-H, p-F, p-Me, p-OMe). [20][21][22] Benzylidene transfer from (CO) 5 WdCHPh to the thiocarbonyl group in thiobenzophenones results in thiirane complexes. 23 The same complexes can also be prepared by reaction of the corresponding (CO) 5 W-(thiobenzophenone) complex with diphenylazomethane.…”

“…[20][21][22] Benzylidene transfer from (CO) 5 WdCHPh to the thiocarbonyl group in thiobenzophenones results in thiirane complexes. 23 The same complexes can also be prepared by reaction of the corresponding (CO) 5 W-(thiobenzophenone) complex with diphenylazomethane. The thiirane ligands can be readily displaced from the metal either by reaction with NEt 4 -Br in dichloromethane or with pyridine in THF.…”

Synthesis and Transformation of Halochromones

“…Over the last decade, synthetic transformations assisted by transition metal catalysis have emerged [131][132][133][134][135] and halochromones chemistry is clearly not an exception. Carbon-carbon bond formation by an array of palladium-catalyzed cross-coupling reactions (namely Heck [136][137][138][139], Sonogashira [140][141][142], Suzuki [143][144][145] and Stille [146] reactions) are of great importance.…”

Two-fold tandem acyl-group shift/cyclization via gold catalysis

“…[3][4][5][6] Selective carbocyclization by activation of unsaturated C-C multiple bonds in acyclic precursors under transition metal catalyses plays a relevant role in this context mainly thanks to its unique possibility to overcome limitations connected to other conventional methods. 4,[7][8][9][10][11][12][13][14][15][16][17] In this field, gold-catalyzed cycloisomerization reactions of poly-unsaturated substrates received the attention of many research groups in the last few years. [18][19][20] Recently, a straightforward access to polyconjugated Gold catalyst Scheme 1.…”