Chemoselective reductive alkylation of ammonia with carbonyl compounds: synthesis of primary and symmetrical secondary amines

Zinc(II)‐Catalyzed Synthesis of Propargylamines by Coupling Aldimines and Ketimines with Alkynes

“…[28] When benzylamine was treated with butanone and phenylacetylene in the presence of 20 mol-% of Zn(OTf ) 2 and 4 Å molecular sieves (MS) or Ti(OiPr) 4 as a drying agent, we were gratified to observe a 15-20 % conversion into the corresponding propargylic amine. Because the formation of the imine is crucial for this conversion, further optimization studies focused on the ketimines, which were prepared from ketones and the appropriate primary amine in the presence of either activated molecular sieves, [29] concentrated HCl, [30] or Ti(OiPr) 4 [31] as water scavengers. In our first attempt, N-propylcyclohexanimine (4a) was treated under the conditions for the aldimine coupling reaction.…”

Enantioselective Syntheses of Pachastrissamine and Jaspine AviaHydroxylactonization of a Chiral Epoxy Ester

“…The stereoselective reductive amination of 21 to 22 was achieved by using Bhattacharyya's protocol (NH 3 /Ti(Oi-Pr) 4 in EtOH, and then NaBH 4 ), 26) furnishing desired reductive amination product 22 as a single stereoisomer in a 60% yield; on the other hand, exposure of 21 to conventional reductive amination conditions (NaCNBH 3 /NH 4 OAc in MeOH) gave none of the desired product, resulting only in reduction of the ketone functionality to give alcohol 18. Finally, deprotection of the TBS group with TBAF gave pachastrissamine 1 in a 90% yield.…”

Fluorescence‐Based Kinetic Assay for High‐Throughput Discovery and Engineering of Stereoselective ω‐Transaminases

“…Efficient reductive amination of the resultant ketones 2a-c wasp erformed by titaniummediated imination with ammonia followed by borohydride reduction [19] to furnish the racemica mines 1a-c in high overally ields.…”