Facile Synthesis of Morpholines and Azacrown Ethers by Ozonolysis of Cyclic Olefins and ReductiveN-Alkylation

An Asymmetric Synthesis of 2-Substituted Piperidines through Ozonolysis of Cyclopentenes and Reductive Aminocyclization

“…The reactivity of 2b for la was low and it took 6 days to complete the aminocyclization. The reaction with 1b and 2b was so slow that the corresponding 1,2-disubstituted piperidine (3) having propyl and t·(Inaphthyl)ethyl groups could not be obtained in a practical yield. The major isomer of the diastereomeric piperidine 3b was successfully isolated by silica gel column chromatography.…”

“…3 ) This series of reactions_ could be applied to an asymmetric synthesis of 2-substituted piperidines from I-substituted cyclopentenes when an optically active amine is employed. Thus we undertook syntheses of the optically active -piperidines 4a, 4b, 7 and 11, having methyl, propyl, carboxyl and hydroxymethyl groups, ,respectively.…”

Intermolecular, Markovnikov Hydroamination of Vinylarenes with Alkylamines.

“…The reaction mixture was purified by flash column chromatography (20% EtOAc in hexane) to give 168 mg (76%) of the hydroamination product. 1 H NMR (400 MHz, CDCl 3 , TMS) d 1.33 (d, J = 6.8 Hz, 3H), 2.29-2.39 (m, 2H), 2.40-2.52 (m, 2H), 3.26 (q, J = 6.8 Hz, 1H), 3.68 (t, J = 4.7 Hz, 4H) 3.79 (s, 3H), 6.78-6.88 (m, 2H), 7.16-7.26 (m, 2H); 13 C{ 1 2, Entry 4). The general procedure was followed with 2-vinylnapthalene (308 mg, 2.00 mmol) and morpholine (87.0 mg, 0.99 mmol).…”

“…2, Entry 1). 3 The general procedure was followed with styrene (229 ml, 2.00 mmol) and morpholine (87.2 mg, 1.00 mmol). The reaction mixture was purified by flash column chromatography (10% EtOAc in hexane) to give 144 mg (75%) of the hydroamination product: 1 H NMR (400 MHz, CDCl 3 , TMS) d 1.45 (d,…”

An Asymmetric Synthesis of Lactones from Cyclic Acid Anhydrides with Chiral Binaphthyldiamines

“…A one-pot synthesis through ozonolysis of 2,5-dihydrofuran and subsequent reductive N-alkylation gave the morpholino derivative ld in a 42% yield. 12 ) Taking account of naturally occuring lactones or the analogs, the prochiral acid anhydrides 2,,-, 6 were subjected to the present asymmetric synthesis. o The stereoselectivity of the asymmetric ring opening was assessed on the diastereoisomeric ratios of the amide-esters (IV) by HPLC (Scheme 1).…”