Erschöpfende α‐Alkylierung von Fünfring‐Ketonen mit Natriumhydrid und Dimethylsulfat oder Ethyliodid

Abstract

Exhaustive α‐Alkylation of Five‐Membered Ring Ketones by Sodium Hydride and Dimethyl Sulfate or Ehtyl Iodide Cα‐Permethylation may be carried out by addition of a basesensitive ketone like cyclopentanone to the inexpensive and stable mixture of sodium hydride and dimethyl sulfate. Exhaustive Cα‐ethylation is exemplified with sodium hydride by simultaneous introduction of ketone 4 and ethyl iodide. The 13C‐NMR absorptions of 1,3‐alkylated 2‐indanones 3–5 are assigned and some of the CH coupling constants reported.

Disila-Phantolide and Derivatives: Synthesis and Olfactory Characterization of Silicon-Containing Derivatives of the Musk Odorant Phantolide

“…The solvent of the filtrate (including the eluate) was removed under reduced pressure, and the residue was purified by bulb-to-bulb distillation (90-100°C/ 0.02 mbar) to afford compound 7 in 77% yield as colorless crystals (414 mg, 1.59 mmol); mp 53-54°C. 1 29 Si NMR (59.6 MHz, C 6 D 6 ): δ -3.9, -3.6. Anal.…”

“…A B€ uchi GKR 50 apparatus was used for the bulb-to-bulb distillations. The 1 H, 13 C, and 29 Si NMR spectra were recorded at 23°C on a Bruker Avance 500 ( 1 H, 500.1 MHz; 13 C, 125.8 MHz; 29 Si, 99.4 MHz) or a Bruker DRX-300 NMR spectrometer ( 1 H, 300.1 MHz; 13 C, 75.5 MHz; 29 Si, 59.6 MHz) using C 6 D 6 or CD 2 Cl 2 as the solvent. Chemical shifts (ppm) were determined relative to internal C 6 HD 5 ( 1 H, δ 7.28; C 6 D 6 ), C 6 D 6 ( 13 C, δ 128.0; C 6 D 6 ), CHDCl 2 ( 1 H, δ 5.32; CD 2 Cl 2 ), CD 2 Cl 2 ( 13 C, δ 53.8; CD 2 Cl 2 ), or external TMS ( 29 Si, δ 0; C 6 D 6 , CD 2 Cl 2 ).…”

“…1 , 1 H, H-7), 7.89 (s, 1 H, H-4). 13 C NMR (125.8 MHz, C 6 D 6 ): δ -1.2 (2 C, SiCH 3 ), -0.9 (2 C, SiCH 3 ), 21.7 (CCH 3 ), 29.2 (C(O)CH 3 ), 132.6 (C-4), 136.2 (C-7), 138.4 (C-5 or C-6), 139.4 (C-5 or C-6), 140.5 (CCH 2 ), 146.5 (C-3a or C-7a), 153.1 (CCH 2 ), 153.6 (C-3a or C-7a), 201.0 (C(O)CH 3 ). 29 Si NMR (99.4 MHz, C 6 D 6 ): δ -4.22, -4.19.…”

“…Chemical shifts (ppm) were determined relative to internal C 6 HD 5 ( 1 H, δ 7.28; C 6 D 6 ), C 6 D 6 ( 13 C, δ 128.0; C 6 D 6 ), CHDCl 2 ( 1 H, δ 5.32; CD 2 Cl 2 ), CD 2 Cl 2 ( 13 C, δ 53.8; CD 2 Cl 2 ), or external TMS ( 29 Si, δ 0; C 6 D 6 , CD 2 Cl 2 ). Assignment of the 1 H NMR data was supported by 1 H, 1 H gradient-selected COSY, 13 C, 1 H gradient-selected HMQC and gradient-selected HMBC, and 29 Si, 1 H gradient-selected HMQC experiments (optimized for 2 J Si,H = 7 Hz). Assignment of the 13 C NMR data was supported by DEPT135 and the aforemen- 1-(1,1,2,3,3,6-Hexamethyl-1,3-disilaindan-5-yl)ethanone (Disila-phantolide, 4).…”

“…13 C NMR (75.5 MHz, C 6 D 6 ): δ 2.9 (4 C, SiCH 3 ), 145.8 (CCH 2 ), 148.0 (CCH 2 ). 29 12.5 mmol), and a 0.1 M solution of cobalt(II) iodide in acetonitrile (2.57 mL, 257 μmol of CoI 2 ) were added in single portions one after another at 20°C to a stirred suspension of zinc powder (67 mg, 1.02 mmol) in acetonitrile (20 mL). 24 The reaction mixture was stirred at ca.…”