Asymmetric carbon–carbon bond‐forming reaction at the 2‐position of a piperidine skeleton

Abstract

An asymmetric carbon-carbon bond-forming reaction at the 2-position of a piperidine skeleton was exploited. This method consisted of a reaction between 1-(4-methoxybenzoyl)-3,4-didehydro-2-methoxypiperidines and dimethyl malonate catalyzed by Cu(II)-chiral 2,2'-isopropylidenebis(4-phenyl-2-oxazoline) to afford a 2-substituted piperidine skeleton with moderate enantioselectivity.

Highly Efficient CuBr‐Catalyzed Cross‐Dehydrogenative Coupling (CDC) between Tetrahydroisoquinolines and Activated Methylene Compounds

“…The copper catalyst also activates the malonate. [9] Subsequently, coupling of the two intermediates results in the desired product and regenerates the copper catalyst. Alternatively, it is possible that tert-butyl peroxide products are involved as intermediates [3b,10] which are further converted into the corresponding cross-coupling products with CuBr.…”

C2-Symmetric Chiral Bis(Oxazoline) Ligands in Asymmetric Catalysis

“…Dimethyl malonate is the alkylating agent of 1-substituted 3,4-dehydro-2-methoxypiperidines ( 184 , R = COAr and CO 2 Me), and ( R )- 185 are the products when [( S )- 1 /Cu(OTf) 2 ] is used as the catalyst: 34−78% yields and 41−53% ee were obtained, while [( S )- 2 /Cu(OTf) 2 ] gave lower enantiomeric excesses (Scheme ) 65 …”

The Shono-type electroorganic oxidation of unfunctionalised amides. Carbon–carbon bond formation via electrogenerated N-acyliminium ions

“…The direct anodic oxidation reaction to afford the N -acyliminium ion can be intercepted with a carbon nucleophile enantioselectively when a chiral auxiliary is attached either to the carbamate or amide ( Fig. 5 ) [ 69 – 71 ] (using a platinum anode and tungsten cathode electrochemical set-up) [ 69 ] or the use of Cu-PyBox chiral ligand systems [ 72 ].…”