A CpRh(III) complex catalyzes reductive amination of ketones using HCOONH(4) at 50-70 degrees C to give the corresponding primary amines in high yields. The reaction is clean and operationally simple and proceeds at a lower temperature and with higher chemoselectivity than the original Leuckart-Wallach reaction. The new method has been applied to the synthesis of alpha-amino acids directly from...

Lividamine and paromamine were converted into two key intermediate ethylenic aldehydes 10a and 10b. Reductive amination of the two aldehydes yielded the protected sisamine 11a and the three analogs 11b, 12a and 12b. These four derivatives were deprotected to yield the four pseudodisaccharides 1a, 1b, 2a and 2b which were less active in vitro than neamine against Escherichia coli ATCC 9637 and S...

Reductive aminases (RedAms) have recently emerged as promising biocatalysts for the synthesis of chiral secondary amines by coupling primary with aldehydes/ketones. However, access to tertiary remains more problematic, particularly when ketones amines. Here we show that scope these enzymes can be extended allow selective reductive aminations cyclic amines, such piperidines and morpholines, both...

A series of new 1-aryl-4-(biarylmethylene)piperazines has been synthesized. These ligands are structurally related to SLV-313, a potential atypical antipsychotic having potent D2 receptor antagonist and 5-HT1A receptor agonist properties. Buchwald-Hartwig coupling reactions of 1-boc-piperazine with appropriate aryl halides and subsequent removal of the boc group rendered arylpiperazines. The re...

A small library of truncated neomycin-conjugates is prepared by consecutive removal of 2,6-diaminoglucose rings, oxidation-reductive amination of ribose, oxidation-conjugation of aminopyridine/aminoquinoline and finally dimerization. The dimeric conjugates were evaluated for antibacterial activity with a unique hemocyanin-based biosensor. Based on the outcome of these results, a second-generati...

DNA interstrand cross-links (ICLs) are the clinically most relevant adducts formed by many antitumor agents. To facilitate the study of biological responses triggered by ICLs, we developed a new approach toward the synthesis of mimics of nitrogen mustard ICLs. 7-Deazaguanine residues bearing acetaldehyde groups were incorporated into complementary strands of DNA and cross-link formation induced...

The protecting-group-free asymmetric synthesis of 1,2,4-trideoxy-1,4-imino-L-xylitol is readily achieved in five steps from 2-deoxy-D-ribose and with an overall yield of 48%. Key in this synthesis is the application of our recently developed Vasella-reductive amination and carbamate annulation methodologies to the synthesis of 2-deoxy-aza-sugars. The carbamate annulation occurred with excellent...

A new sequential organocatalytic method for the synthesis of chiral 3-substituted (X = OH, NH2) tetrahydroquinoline derivatives (THQs) [ee up to 99%, yield up to 87%] based on α-aminooxylation or -amination followed by reductive cyclization of o-nitrohydrocinnamaldehydes has been described. This methodology has been efficiently demonstrated in the synthesis of two important bioactive molecules ...

Abstract An asymmetric hydrogenation of enamines is efficiently catalysed by rhodium complexed with a fluorinated version the planar chiral paracyclophane-diphosphine ligand, Phanephos. This catalyst was shown to be very active, examples operating at just 0.1 mol% catalyst. then successfully adapted Direct Asymmetric Reductive Amination, leading formation several tertiary amines moderate ee, if...

A new cobalt catalyst is presented for the domino hydroformylation-reductive amination reaction of olefins. The optimal Co-tert-BuPy-Xantphos shows good to excellent linear-to-branched (n/iso) regioselectivity reactions aliphatic alkenes with aromatic amines under mild conditions. This system far more selective than traditional cobalt(I) catalysts and even better most known rhodium catalysts.