Synthesis of 4-tert-butyl-1,1-dimethylindan and 7-tert-butyl-3,3-dimethyl-1-indanone and a comparison of isomers

Abstract

cis-Hydrindenol 13a. To a stirred solution of 189 mg (0.5 mmol) of p-toluenesulfonylhydrazone 18 and 4 mL of tetramethylethylenediamine in 3 mL of anhydrous ether at 0 °C under nitrogen was added dropwise 3 mL of a 1 M solution of methyllithium in diethyl ether. The reaction mixture was stirred overnight at room temperature. Then, 20 mL of water was carefully added, and the organic layer was separated, washed several times with water, and dried over anhydrous magnesium sulfate. Concentration afforded 94 mg of crude material which was subjected to preparative TLC (silica gel, 1:1 benzene/EtOAc) to give 74 mg (76%) of colorless oil: NMR (CDC13) 0.93 (s,3 ), 1.08 (d, J -6 Hz, 3 H), 3.22-3.77 (m, 2 H), 5.53 (hr s, 2 H);

Iridium‐Catalyzed Asymmetric Hydrogenation of Unfunctionalized Exocyclic C=C Bonds

“…To demonstrate the potential application of this simple and highly efficient catalytic asymmetric hydrogenation, we prepared a key intermediate required for the synthesis of an insecticide . Our hydrogenated product was oxidized with CrO 3 in AcOH/H 2 O with 58 % yield and 93 % ee , then reduced to (1 S ,3 R )‐3‐benzyl‐2,3‐dihydro‐1 H ‐inden‐1‐ol. Enantioselectivity was retained with >20:1 d.r.…”

“…Other types of phosphine-oxazoline ligands, such as tBu-PHOX (L5), planar-chiral mono-tBu-Ru-PHOX( L6), and (aS)-tBu-Binaph-PHOX (L7)w erea lso screened. Unfortunately,t hey only yielded trace amountso fp roduct (entries [13][14][15]. To our delight,i f 1 mLo fA cOH was used as an additive in the reaction, the hydrogenation proceeded smoothly and provided the best over-all performance with full conversion and 93 % ee (entry 16).…”

Rhodium-Catalyzed Oxidative Coupling/Cyclization of 2-Phenylindoles with Alkynes via C−H and N−H Bond Cleavages with Air as the Oxidant

“…The yield of 3n was significantly improved up to 94% by using a stoichiometric amount of AgOAc as the oxidant (entry 7). Note that the hydroxymethyl group can act as a leaving group for further fucntionalization …”

Heck-type 5-endo-trig cyclizations promoted by vinylic fluorines: Ring-fluorinated indene and 3H-pyrrole syntheses from 1,1-difluoro-1-alkenes

“…1 3.2.6. 3,3-Dimethylindan-1-one (12) [29] To a solution of PPh 3 (50.8 mg, 0.194 mmol) and Pd(PPh 3 ) 4 (180 mg, 0.156 mmol) in DMA (10 mL) was added 4 (51.5 mg, 0.156 mmol). After the reaction mixture was stirred at 110 8C for 9 h, phosphate buffer (pH 7) was added to quench the reaction.…”