Stereoselective synthesis of N-heterocycles: application of the asymmetric Cu-catalyzed addition of Et2Zn to functionalized alkyl and aryl imines

1.04 Regio-, Diastereo-, and Enantioselective Addition of Organocopper Reagents onto CO and CN Bonds

“…19 3.53 0. 56 In the case of allenyl metals, an open TS, in which the aldehyde reacts at the opposite side of the metal center, is proposed to explain the syn-selectivity (Scheme 11), and the Yamamoto−Chodkiewicz 16 six-membered TS to explain the anti one (Scheme 11).…”

“…After addition of the copper reagent, the corresponding amines 98 were obtained in good yields and enantioselectivities (Scheme 34). 56 A similar procedure has been used for the enantioselective preparation of α,α′,α″-trisubstituted trifluoromethyl amines 99 (ee up to 99%, equation 21). In this case, the ketimine precursor is a stable, isolable, and easily prepared hemiaminal 100 The use of copper enolates has emerged at the outset of this century as an efficient tool for the catalytic and enantioselective construction of aldol (Mannich)-type moieties (see Chapter 2.10 for an overview on metal enolate chemistry).…”

Synthesis and crystal structure of a novel prochiral ketoimine: (E)-acetophenoneO-diphenylphosphoryl oxime

“…Aldehydes and ketones may be used to produce chiral secondary alcohols (Baker-Salisbury et al, 2014) and tertiary alcohols (Garcia et al, 2002), respectively. Aldimine and ketoimine substrates may be used to prepare, respectively, chiral tertiary (Bonnaventure & Charette, 2009;Soai et al, 1992) and quaternary (Cogan & Ellman, 1999) hydrocarbon substituents on amines. In contrast to aldehyde and ketone addition reactions, much less has been reported about imine addition (Fu et al, 2008;Nishimura et al, 2012).…”

Asymmetric Synthesis of 2‐Heteroaryl Cyclic Amines: Total Synthesis of (–)‐Anabasine

“…Existing approaches for synthesizing cyclic amines with stereogenic centers at the C2 position are generally based on one of the following processes as the key step: ring‐closing metathesis of disubstituted branches linked to a chiral amine,7 asymmetric direct α‐functionalization of the corresponding saturated cyclic amines,2 asymmetric hydrogenation8 or allylboration9 of cyclic imines, addition to pyridinium salts bearing a chiral auxiliary,10 and catalyzed asymmetric addition of diethylzinc to imines 11. Thus, synthesis of enantiopure 2‐substituted piperidine derivatives still constitutes an area of current interest and alternative methods are currently the object of intensive synthetic endeavors.…”