Hydroacylation of 2-Vinyl Benzaldehyde Systems:  An Efficient Method for the Synthesis of Chiral 3-Substituted Indanones

Abstract

Asymmetric rhodium-catalyzed hydroacylation has been utilized in the synthesis of 3-substituted indanones with high conversions and enantioselectivity. The hydroacylation reaction of 2-vinyl benzaldehyde had been previously reported to give a low yield of indanone and an unidentified product. We have identified this compound as a dimer of the starting material. Substitution at the alpha-position of the 2-vinyl benzaldehyde substrates blocks the competitive dimerization reaction and allows the reaction to proceed with yields generally greater than 90%. Utilization of BINAP as a chiral ligand results in good chemical yields and enantioselectivity greater than 95% in most cases.

An Unprecedented Rhodium‐Catalyzed Asymmetric Intermolecular Hydroacylation Reaction with Salicylaldehydes

“…Later this approach was extended by Sakai, Bosnich and Morehead, who achieved high enantioselectivities with other substrates. [8][9][10] Tanaka, Sakai and Suemune developed the asymmetric intramolecular hydroacylation reaction further into efficient desymmetrizations of symmetric dienals. [11] The intermolecular hydroacylation reaction has been studied much less than its intramolecular counterpart.…”

Functionalization of Acetalic C(sp3)‐H Bonds by Scandium(III) Triflate‐Catalyzed Intramolecular Redox Reactions: Tandem 1,4‐Hydride Transfer/1,5‐Cyclization Processes Leading to Protected 1‐Indanones

“…The original Rh-catalyzed reaction was reported to proceed in an extremely sluggish way with benzaldehydes bearing b-substituted 2-vinyl groups. [11] With the acetal-hydrolyzed ortho-formylbenzylidenemalonate 3a in our hands as result of our initial attempts, we could prove that 3a did not convert into the indanone 5a under the habitual reaction conditions, thus ensuring that compounds 4 are intermediates in the processes leading from 2 to 5.…”

One‐Pot Olefin Isomerization/Aliphatic Enamine Ring‐Closing Metathesis/Oxidation/1,3‐Dipolar Cycloaddition for the Synthesis of Isoindolo[1,2‐a]isoquinolines

“…Amine 3c was obtained from 2-(a-styryl)benzaldehyde [26] (2.81 g, 13.5 mmol) as ap ale yellow oil;y ield:2 .28 g( 9.16 mmol, 68%); General Procedure for N-Allyl-N-benzyl-(2-vinylbenzyl)amine Derivatives (1a, 1b, and 1c) …”