A study on the regio- and stereoselectivity in palladium-catalyzed cyclizations of alkenes and alkynes bearing bromoaryl and nucleophilic groups

Catalytic conjunctive cross-coupling enabled by metal-induced metallate rearrangement

“…Subsequent reductive elimination ( IV → I ) would serve to establish a second C-C bond, release the product, and concomitantly furnish a reduced Pd complex that might continue a catalytic cycle. Although π-acidic late transition metal complexes are well known to activate alkenes for nucleophilic attack, nucleopalladation with Pd(II) complexes generated by oxidative addition reactions are less common (18,19). For the envisioned process to be successful, several key questions emerged: Would the Pd(II) aryl complexes be sufficiently π-acidic to facilitate metallate rearrangement ( III → IV )?…”

Direct and Short Construction of the ACDE Ring System of Daphenylline

“…We envisioned that the D ring of the bowl‐shaped framework 4 could be reached by an intramolecular Friedel–Crafts acylation of acid 5 , a derivative from aldehyde 6 through a sequence of Horner–Wadsworth–Emmons reaction, hydrogenation of the corresponding double bond, and hydrolysis. Tricyclic compound 6 would be produced by a radical cyclization of the pyrroline 7 , which could be achieved from the known alkyne 8 9 and aldehyde 9 10 by an iron(III)‐catalyzed aza‐Cope‐Mannich reaction.…”

“…As summarized in Scheme , the synthesis commenced with the known 3‐(2‐bromophenyl)propanal ( 9 ), which was prepared from the commercially available 1‐bromo‐2‐iodobenzene ( 10 ) by a Jeffery–Heck coupling with allyl alcohol in 76 % yield 10. The obtained aldehyde 9 and the known alkyne 8 were then subjected to the aza‐Cope‐Mannich reaction conditions to obtain the corresponding pyrroline 7 in 91 % yield in the presence of FeCl 3 9.…”

Synthesis of 2-Alkenyl-Tethered Anilines

“…To an oven-dried, 250-mL, round-bottomed flask equipped with a magnetic stir bar were added bromo alcohol 16 24 (3.21 g, 11.9 mmol) and CH 2 Cl 2 (120 mL, 0.1 M), and then the flask was connected to an argon inlet. The solution was cooled to 0 °C in an ice bath, and Et 3 N (5.83 mL, 41.8 mmol, 3.5 equiv) and MsCl (1.38 mL, 17.9 mmol, 1.5 equiv) were added by syringe.…”