Step‐Economical Synthesis of Taxol‐like Tricycles through a Palladium‐Catalyzed Domino Reaction

‘One-pot’ Synthesis of Dihydrobenzo[4,5][1,3]oxazino[2,3-a] isoquinolines via a Silver(I)-Catalyzed Cascade Approach

“…Compared to the stepwise approach, cascade reactions represent an attractive strategy in synthesis because multiple bond-forming and -cleaving events can be combined into a single reaction operation. Recently, transition-metal-catalyzed cascade processes have received significant attention [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. Among these transition metals, silver salts have long been believed to have low catalytic efficiency, and most commonly served as either co-catalysts or weak Lewis acids [ 20 ].…”

Total Synthesis of Rubriflordilactone B

“…Selenide attack (o-NO 2 C 6 H 4 SeCN,N aBH 4 )f ollowed by oxidation and elimination gave diene 6 in 50 %y ield over the two steps.A n enone generated by a[2,3]-sigmatropic rearrangement of the selenoxide intermediate was detected as as ide product. At this point, the enantiopurity of the left-hand fragment was determined by HPLC analysis of an aromatic derivative of 22 (96 % ee,s ee the Supporting Information).…”

“…[1][2][3] Thecombination of 6p electrocyclization and oxidative aromatization for constructing multisubstituted arenes is of significant advantage from the following aspects:1 )strong driving force,2 )nof unctionalization (e.g., halogenation or metalation) required, 3) separating stereochemical problems from connectivity issues,4 )eliminating torquoselectivity issues, and 5) enhanced convergence.T hus,s uch strategies were creatively applied by an umber of groups in synthesizing natural products containing multisubstituted arenes, [4,5] which recently inspired us to explore this area. Theg roups of Nicolaou and others have elegantly demonstrated the power of electrocyclization in natural product synthesis.…”

“…Theg roups of Nicolaou and others have elegantly demonstrated the power of electrocyclization in natural product synthesis. [1][2][3] Thecombination of 6p electrocyclization and oxidative aromatization for constructing multisubstituted arenes is of significant advantage from the following aspects:1 )strong driving force,2 )nof unctionalization (e.g., halogenation or metalation) required, 3) separating stereochemical problems from connectivity issues,4 )eliminating torquoselectivity issues, and 5) enhanced convergence.T hus,s uch strategies were creatively applied by an umber of groups in synthesizing natural products containing multisubstituted arenes, [4,5] which recently inspired us to explore this area. [6,7] However, the geometrically controlled formation of the prerequisite triene substrates is ac onsiderable challenge for executing the electrocyclization strategy.P artial-hydrogenation reagents (e.g.,L indlar catalyst, diazene,a ctivated Zn) suffer from incompatibility issues with functionalized diene-ynes and result in poor yields of the desired cis-trienes.P recursors of penta-and hexasubstituted arenes pose even greater difficulties in controlling the geometry of the more substituted olefin substrates.…”

Oligoene‐Based π‐Helicenes or Dispiranes? Winding up Oligoyne Chains by a Multiple Carbopalladation/Stille/(Electrocyclization) Cascade

“…Te trasubstituted alkenes are easily obtained by carbopalladation reactions of alkynes. [9][10][11][12][13] The organometallic species [Pd]À Rc ommonly attacks the reacting p-systemi nasyn-fashion, which leads to alkene moieties bearingP da nd Ro nt he same side (Scheme 1). This special feature is the prerequisite for accessingo ur target structures.…”