Asymmetric induction in Darzens condensation by means of (−)-8-phenylmenthyl and (−)-menthyl auxiliaries

Lithiation of 1-Chloromethylbenzotriazole: Generation and Elaboration of Benzotriazolyloxiranes

“…The synthetic potential of carbenoids, in particular α-haloalkyllithiums, is well documented . α-Haloorganometals and metalloids derived from alkyl and allyl halides, α-halo-esters, -amides, and -nitriles, 2-halomethylbenzothiazoles, 2-halomethyloxazoles, and 2- and 3-halomethylpyridines can be trapped effectively with carbonyl compounds to give oxiranes.…”

Synthesis of Functionalized Tetracyanocyclopentadienides from Tetracyanothiophene and Sulfones

“…A mixture of (1 R ,3 R ,4 S )-menthyl bromoacetate (276 mg, 1.0 mmol, 1.0 equiv), sodium p -toluenesulfinate (715 mg, 4.0 mmol, 4.0 equiv), and DMF (20 mL) was stirred at room temperature for 24 h. After addition of water (20 mL), the resulting mixture was extracted with EtOAc, and the organic layer was washed with water and brine, dried over MgSO 4 , filtered, and concentrated. Flash chromatography (20% EtOAc/ n -hexane) afforded 415 mg (96%) of 18e as a colorless solid: mp 93–94 °C; [α] 23 D −45.0 ( c 1.01, CHCl 3 ); IR (KBr) 2960, 2870, 1735, 1324, 1294, 1148, 1087 cm –1 ; 1 H NMR (CDCl 3 , 500 MHz) δ 7.82 (2H, d, J = 8.3 Hz), 7.37 (2H, d, J = 8.3 Hz), 4.66 (1H, td, J = 11.0, 4.4 Hz), 4.09 (2H, s), 2.46 (3H, s), 1.88 (1H, dddd, J = 11.9, 4.4, 3.4, 2.1 Hz), 1.75 (1H, sept-d, J = 6.9, 2.6 Hz), 1.68–1.63 (2H, m), 1.42 (1H, tqt, J = 12.0, 6.4, 3.4 Hz), 1.33 (1H, dddd, J = 12.1, 11.0, 3.3, 2.6 Hz), 1.00 (1H, tdd, J = 13.5, 12.0, 3.9 Hz), 0.90 (1H, ddd, J = 12.1, 12.0, 11.9 Hz), 0.89 (3H, d, J = 6.4 Hz), 0.844 (3H, d, J = 6.9 Hz), 0.836 (1H, tdd, J = 13.5, 12.0, 3.9 Hz), 0.69 (3H, d, J = 6.9 Hz); 13 C NMR (CDCl 3 , 125 MHz) δ 162.0, 145.2, 135.8, 129.8, 128.6, 76.7, 61.2, 46.6, 40.3, 34.0, 31.3, 25.8, 23.1, 21.9, 21.7, 20.7, 16.0; HRFABMS m / z calcd for C 19 H 27 O 4 S [M – H] − 351.1630, found 351.1633.…”

Aziridine Synthesis via Nucleophilic Attack of Carbene Equivalents on Imines: the Aza‐Darzens Reaction

“…N-Diphenylphosphinyl-("N-Dpp")benzaldimines react with chiral α-bromoacylsultams to give diastereomerically pure aziridines in good yield (Table 4). [26] Carbonyl stabilization of anions is not a pre-requisite for aza-Darzens reactions, and adjacent alkenyl or benzylic substitution can facilitate the processes. Asymmetric aza-Darzens by reagent control: using chiral sultamoyl enolates.…”