Reversal of Diastereofacial Selectivity in Hydride Reductions of N-tert-Butanesulfinyl Imines

Abstract

A variety of N-tert-butanesulfinyl imines were reduced with NaBH4 in THF containing 2% water to provide the corresponding secondary sulfinamides in high yield and diastereoselectivity. By using the same sulfinyl imine starting materials and changing the reductant to L-Selectride, the stereoselectivity could be efficiently reversed to afford the opposite product diastereomer in high yield and selectivity.

Isolation of Functionalized Phenolic Monomers through Selective Oxidation and CO Bond Cleavage of the β‐O‐4 Linkages in Lignin

“…[21][22][23] A recent report has shown that 12 can be produced as a mixture with other phenolic monomers through bimetallic hydrogenolysis of organosolv lignin in water.…”

Highly Enantio‐ and Diastereoselective Synthesis of γ‐Amino Alcohols from α,β‐Unsaturated Imines through a One‐Pot β‐Boration/Reduction/Oxidation Sequence

“…Entries 11-20 in Table 1 show that the phenyl substituent on the imino group of 1b notably decreases the reactivity of the substrate in the Cu(I)-mediated catalytic b-boration reaction. The average enantioselectivity also significantly decreases, however, we were particularly delighted to see that one of the most accessible chiral ligands, the monodentate phosphoramidite L9, promotes the formation of 2b in quantitative yield and with 95% ee (Table 1, entry 19).…”

“…Faul and co-workers highlighted the influence of the solvent on syn:anti-diastereoisomer ratios in the reduction of sulfinamides using NaBH 4 . [19] Inspired by these examples, we also carried out reductions of 2a with NaBH 4 in wet THF (2% H 2 O) and MeOH. While NaBH 4 in wet THF produced similar results to those obtained with NaBH 4 in EtOH (Table 2, entry 3), the reduction in MeOH gave the anti-diastereoisomer with high selectivity (Table 2, entry 4).…”

Simple Preparation of New Potential Bioactive Nitrogen-Containing Molecules and Their Spectroscopy Analysis

“…Thus, the N-aryl imine 6, the main and value starting, can be prepared from commercially available 3-indolaldehyde 4 and 2-cyanoaniline 5, according to published methods (Colyer et al, 2006). This aldimine is obtained as a white and stable solid after purification by recrystallization in 95 % yield (Fig.…”