Transformation of an Optically Active Decahydro‐6‐isoquinolone Scaffold: Perfect Felkin—Anh Diastereoselectivity.

Abstract

Scaffold: Perfect Felkin-Anh Diastereoselectivity. -The first optically active decahydro-6-isoquinolone derivative (II) with a quaternary stereocenter is synthesized. The racemic aldehyde reacts with a number of different Grignard reagents to give the secondary alcohols in good yields as single diastereomers. High diastereoselectivity for the addition of nucleophiles to carbaldehyde groups in a neopentyl environment has not been reported so far. -(CHRISTOFFERS*, J.; SCHARL, H.; FREY, W.; BARO, A.; Org. Lett. 6 (2004) 7, 1171-1173; Inst. Org. Chem., Univ. Stuttgart, D-70569 Stuttgart, Germany; Eng.) -Steudel 33-164

Michael Reactions and Conjugate Additions

“…The absolute configuration agrees perfectly with the working model outlined in Scheme 4.35 [93]. Enamines such as 68a coordinate as tridentate ligands with one six-membered azadiketonate chelate and one five-membered ring to Cu(II).…”

Aminodecalone Scaffolds – Enantioselective Synthesis, Indole and Quinoline Annulation

“…The more polar isomer 17 was obtained with 32 % and 92 % ee . The absolute configuration of the quaternary stereocenter was assigned according to observations previously made with the same auxiliary . For the relative configuration of the nitro‐bearing stereocenter at the 5‐position, it was assumed that the formation of compound 16 with 99 % ee represents the “match“ case, where auxiliary and methyl group direct the electrophile into the same configuration, whereas the formation of compound 17 with only 92 % ee represents the “mismatch“ case with nitro and ester group in relative cis ‐configuration.…”

Asymmetric Michael Reactions on Polymeric Support: Auxiliary Immobilization and Stereoselective Construction of Quaternary Stereocenters

“…According to our mechanistic model, [6] the reaction occurs via intermediate 6 which is formed by deprotonation of the enamine by acetate, followed by coordination of the resulting azadionato anion to the metal ion. Coordination to the amide oxygen leads to a second chelate.…”