Copper ion-catalyzed asymmetric carbon–carbon bond-forming reaction at the 2-position of a piperidine skeleton

Pd(II)-Catalyzed Asymmetric Addition of Malonates to Dihydroisoquinolines

“…First, the cyclic imines 2 react with (Boc) 2 O to give the carbonates 10 . Although uncatalyzed decarboxylation of 10 to the N , O -acetal 11 is not fast, addition of the Pd complex apparently accelerates the reaction, as indicated by vigorous gas evolution. , We speculate that the Pd enolate 12 would be a key intermediate on the basis of our previous results, though this remains to be confirmed. A strong protic acid, generated during the formation of 12 , would facilitate formation of the acyl iminium intermediate 13 , which would react with the Pd enolate to complete the catalytic cycle.…”

2,2-Bis(4(S)-phenyl-1,3-oxazolin-2-yl)propane

“…33 The asymmetric Kharasch-Sosnovsky reaction is a widely used method for asymmetric allylic oxidation. 2-Substituted piperidines are useful synthetic intermediates in the synthesis of a variety of alkaloids and biologically active compounds.…”

The Aminomethylation of Electron-Rich Aromatics with an N-Silyl-N,O-Acetal Catalyzed by a Metal Triflate-TMSCl System: Facile Synthesis of Aromatic Primary Amines, 1-Aryl-trichloroethylamines

“…Lectka et al suggest that a silanol is produced by a direct elimination from an N , O -acetal in a Mannich-type reaction: see refs f,g.…”

“…On the other hand, N , O -acetals, which consist of an sp 3 -carbon attached to both oxygen and nitrogen atoms, are one of the more useful functional groups and have been widely applied to organic synthesis . For example, the in situ generation of the corresponding imine or iminium salt via the selective cleavage of the oxygen atom of the acetal under Brønsted or Lewis acid activation, followed by a reaction with nucleophiles, leads to the formation of a new carbon−carbon bond. − Although a considerable number of the Lewis or protonic acid-mediated aminomethylations of aromatic compounds or heterocycles using an N , O -acetal have been reported, , the Lewis acid- catalyzed aminomethylation of aromatics with an N , O -acetal has not been extensively studied . This appears to be due to the consumption of the acid by coordination to the aromatic amines as well as the extensive use of Friedel−Crafts acylation .…”