Chemistry of gem-Dihalocyclopropanes. III.¹ A New Synthesis of Indenes

Synthesis and Reaction of α‐Dithiolactone

“…We speculated that the extrusion of nitrogen from intermediate 10 would give 4 a. This is another method for the synthesis of 4 a. Refluxing a solution of diazo-1,1,3,3-tetramethylindane (9 b) in carbon disulfide for one day afforded not 4 c but 1,1,2,3-tetramethyl-1H-indene (11) [10] in 58 % yield, suggesting that 9 b did not react with carbon disulfide, and carbene intermediate (12), [11] thus formed by nitrogen extrusion, rearranged to give 11.…”

Synthesis ofo-Dialkenylbenzenes and Indenes Using Heck and Oxypalladation Reactions

“…Ϫ Fraction I: 371 mg (57%) of 3a (R f ϭ 0.54) as a colorless oil. 2-Ethenyl-1-propenylbenzene (3c) and 2,3-Dimethylindene (6c, [25] (Table 1, entry 11): 2-Ethenyl-1-iodobenzene (1.15 g, 5.0 mmol) was treated with styrene (2.60 g, 25.0 mmol) in the presence of palladium acetate (22 mg, 10 mol-%), tetra-n-butylammonium bromide (1.61 g, 5.0 mmol), potassium hydrogen carbonate (2.00 g, 20 mmol) and lithium chloride (210 mg, 5.0 mmol) in NMP (20 ml) at 60°C for 24 h according to GP1. After work-up and column chromatography on silica gel (60 g, eluting with petroleum ether) 392 mg (38%) of pure 8d was obtained as a colorless oil.…”

Precursor directed regioselective synthesis of partially reduced benzo[e]indene through oxidative cyclization and benzo[h]quinolines

“…[8][9][10] It was also synthesized by reaction of gem-dihalocyclopropane and benzene in presence of aluminium chloride. 11 Recently, indene was synthesized by metal catalyzed cycloisomerization of 1-alkyl-2ethynylbenzenes. 12 This reaction can be performed by using PtCl 2 or PtCl 4 or [RuCl 2 (CO) 3 ] 2 as a catalyst at 30-80 C. 12 Au(I) catalyzed [3 + 3] cycloaddition, 13 and Pd-catalyzed carboannulation of propargyl carbonates 14 also provides functionalized indenes.…”