Highly Chemoselective Copper-Catalyzed Conjugate Reduction of Stereochemically Labile α,β-Unsaturated Amino Ketones

Abstract

Highly chemoselective conjugate reduction of chiral alpha,beta-unsaturated amino ketones has been developed by using triisopropyl phosphite ligated copper hydride complex. The highlights of the method are wide substrate compatibility and exceptional chemoselectivity.

Copper(I) carbene hydride complexes acting both as reducing agent and precursor for Cu ALD: a study through density functional theory

“…Copper carbene complexes have a number of uses in organic chemistry. For instance a copper carbene complex with Cl has been widely studied for possible use in alkylation, allylation and reduction in organic chemistry [21][22][23].…”

Enantioselective and Collective Syntheses of Xanthanolides Involving a Controllable Dyotropic Rearrangement of cis‐β‐Lactones

“…In the case of b-lactone 9 i, the phenyl group migrated in the transformation, thus furnishing 10 i in 78 % yield (Table 2, entry 7). [21] On the other hand, the C11 stereogenic center in 8 could be readily inverted by treatment with LDA, thus giving 16, which was transformed into 11b,13-dihydro-tomentosin (7) through a reaction sequence similar to that used in the synthesis of 6. In addition to a-methyl cis-b-lactones, a a-ethyl-cis-b-lactone, 9 l, also underwent the EtAlCl 2 -mediated rearrangement, thus affording 10 l in 76 % yield (Table 2, entry 10).…”

Garner’s aldehyde as a versatile intermediate in the synthesis of enantiopure natural products

“…As with the Wittig reaction, the HWE reaction can also promote the epimerization of the α-proton (p K a of triethoxyphosphonoacetate in DMSO is 18.6) [109]. We have experienced this tendency especially with α-amino ketophosphonates [110], but there is also evidence that aldehyde 1 can lose some of its chiral integrity in the HWE reaction. For base sensitive substrates the use of metal salts (LiCl or NaI) and an amine base (DBU or DIPEA) has proven to be effective in avoiding epimerization [111].…”