Diastereoselective indium-mediated allylation of N-tert-butanesulfinyl ketimines: easy access to asymmetric quaternary stereocenters bearing nitrogen atoms

Abstract

Indium-mediated allylation of N-tert-butanesulfinyl ketimines afforded in high yields and diastereoselectivities homoallylic amine derivatives with the nitrogen atom bonded to a quaternary stereocenter.

High content of pyridinic- and pyrrolic-nitrogen-modified carbon nanotubes derived from blood biomass for the electrocatalysis of oxygen reduction reaction in alkaline medium

“…As shown in Table 2, the percentage of pyridinic-N and pyrrolic-N is severally 52.4% and 33.4% in N-CNT(800), adding up to 85.8%, which may lead to efficient ORR activity. Quaternary N atoms, which possess a 3D structure, are of poor activity in ORR [31]. Besides, compared with other prepared samples, N-CNT(800) has a higher percentage of pyridinic-N species, which was formed by the transformation of pyrrolic-N species during pyrolysis process at a higher temperature.…”

Indium-mediated diastereoselective allylation of N-tert-butanesulfinyl imines derived from α-ketoesters

“…Those are typical reaction conditions developed in our group for the allylation of N-tert-butanesulfinyl imines. 8,9 Under the same reaction conditions, the ethyl imino ester 3b gave compound 5ba in 61% yield (Table 1, entry 4) and, when methallyl bromide (4b) was used as the allylating reagent of for 3b, compound 5bd was obtained in 82% yield (Table 1, entry 5). Crotylation of 3a is a more challenging process, because of the regiochemistry of the addition at the most substituted γ-position of the crotyl indium intermediate took place through a six-membered cyclic transition state, leading to an almost 2:1 mixture of syn an anti-diastereoisomers 5ac (Table 1, entry 2).…”

“…In addition, practical processes for recycling the tert-butanesulfinyl group upon deprotection of N-tert-butanesulfinyl amines have also been reported. 7 Regarding With regards to this, we have described the stereoselective allylation of N-tertbutanesulfinyl aldimines 8 and ketimines 9 with allylindium species and the first one-pot α-aminoallylation of aldehydes with chiral tert-butanesulfinamide, allyl bromides, and indium, which provides homoallylic amines with high chemo-and stereoselectivity. 10 Continuing our interest in this topic, we herein report our first approach to the indium-mediated addition of allylic bromides to N-tert-butanesulfinyl imines derived from α-ketoesters and alkyl glyoxylate esters.…”

Regio- and Stereoselective Aminopentadienylation of Carbonyl Compounds

“…The configuration at the newly stereogenic center formed was controlled by the chiral sulfur atom without remarkable matched or mismatched effect. Encouraged by the good results reported for the indium-mediated allylation of tertbutylsulfinyl ketimines, 17 we decided to apply our pentadienylation methodology to ketones (Scheme 3). In this case the formation of the corresponding ketimines required an increase of the temperature to 60 °C and reaction time to 8 h, whereupon 5-bromo-1,3-pentadiene was added.…”