The total synthesis of indolizomycin

Organometallic Approaches to Carbon–Sulfur Bond Formation

“…Indeed, the use of metal catalysts, including copper, palladium, rhodium and gold, now represents a widely employed synthetic strategy for installation of C-S bonds. The functional group compatibility of these processes continues to increase [11][12][13][14][15], which has led to applications of metal-mediated C-S bond formation in complex molecule synthesis [16][17][18]. Despite these advances, there is continued pressure to develop more efficient and versatile methods.…”

A General Cp*CoIII‐Catalyzed Intramolecular C−H Activation Approach for the Efficient Total Syntheses of Aromathecin, Protoberberine, and Tylophora Alkaloids

“…After reduction of 7 s we could isolate (±)‐septicine ( 8 s ) in 76 % yield, which could then be further transformed via an oxidative coupling to (±)‐tylophorine ( 9 s ) in 90 % yield. After reduction of 7 t under identical conditions, we were able to obtain (±)‐seco‐antofine ( 8 t ) in 96 % yield that could further be oxidized in high yield (85 %) to (±)‐seco‐antofine‐ N ‐oxide ( 9 t ) using m CPBA . (±)‐Julandine ( 8 u ) could be synthesized after reduction of 7 u and after an additional oxidative coupling, we were able to isolate (±)‐cryptopleurine ( 9 u ) in 80 % yield.…”

Efficient Synthesis of Substituted 3‐Azabicyclo[3.1.0]hexan‐2‐ones from 2‐Iodocyclopropanecarboxamides Using a Copper‐Free Sonogashira Coupling

“…[19] Although these proA C H T U N G T R E N N U N G cesses allow a rapid access to the heterocyclic scaffold with particular substitution patterns, the stepwise construction of the two rings in 3-azabicyclo-A C H T U N G T R E N N U N G [3.1.0]hexanes is also a very common and extremely useful strategy. [5,[20][21][22][23][24][25][26][27][28][29] In particular, several methods can be employed to achieve the cyclopropanation of the olefin in unsaturated five-membered nitrogen heterocycles such as imides, lactams or D 3 -pyrrolines. [20][21][22][23][24] Alternatively, 3-azabicycloA C H T U N G T R E N N U N G [3.1.0]hexanes can be synthesized from appropriately functionalized cis-1,2-disubstituted cyclopropanes by using the intramolecular nucleophilic attack of a nitrogen-containing functional group onto an appropriate electrophilic acceptor to achieve ring closure.…”

“…[25,26] In the context of the total synthesis of indolizomycin, Danishefsky et al disclosed the preparation of two examples of 3-azabicycloA C H T U N G T R E N N U N G [3.1.0]hexan-2-ones A, bearing a single substituent at C4 (R'' = H), using the highly diastereoselective nucleophilic capture of an intermediate N-acyliminium ion of type B, either by an intermolecular reaction with allyltrimethylsilane or by a nitrogen-tethered alkenylsilane in an intramolecular fashion. [29] The bicyclic N-acyliminium ions B were generated from hemiaminals C which, in turn, are ac-Abstract: The copper-free Sonogashira coupling between N-substituted cis-2-iodocyclopropanecarboxamides and terminal aryl-, heteroaryl-alkynes or enynes, followed by 5-exo-dig cyclization of the nitrogen amide onto the carbon-carbon triple bond, provides a remarkably efficient access to a variety of substituted 4-methylene-3-aza-…”