Asymmetric Friedel-Crafts alkylations of indoles with dialkyl 3-oxoprop-1-enylphosphonates: Organocatalytic enantioselective synthesis of α-indolyl phosphonates

CAMDOL-enabled diastereoselective synthesis of α-substituted phosphonates

Enantiopure α-substituted phosphonic acids are widely utilized as drugs, pesticides, and ligands. Despite numerous synthetic approaches having been investigated, precise construction of P-adjacent chiral tertiary carbon centres by the employment of recoverable chiral auxiliaries is traditional and still one of the most reliable and practical synthetic methodologies so far. Herein, we present a highly diastereoselective synthesis of α-substituted phosphonates via the unique CAMDOL-derived P-substrates by an efficient sequential deprotonation with LiHMDS and alkylation/arylation with RI. A wide range of 30 structurally diverse α-substituted phosphonate products, including the well-known P-analogues of naproxen and ibuprofen, were thus afforded conveniently in up to 92% yields and 99 : 1 diastereomeric ratios. The related chiral phosphonic acid could be easily obtained by simple acidic hydrolysis with fully recovered auxiliary. This CAMDOL-enabled asymmetric synthetic protocol exhibits comparative advantages over known chiral-induction methods with easy accessibility and compatibility of furnishing a variety of C-stereogenic centres in the proximity of the phosphorus atom, including some rare examples.

Asymmetric Synthesis of Triphenylmethanes via Organocatalytic Regio- and Enantioselective Friedel-Crafts Alkylation of Aniline Derivatives

Herein, we described a highly regio- and enantioselective Friedel-Crafts alkylation of aniline derivatives with in situ generated ortho-quinone methides enabled by chiral phosphoric acid, furnishing a wide range of enantioenriched triarylmethanes bearing three similar benzene rings in high yields (up to 98%) with excellent stereoselectivities (up to 98% ee). Furthermore, the large-scale reactions and diversified transformations of product demonstrate the practicality of the protocol. Density functional theory calculations elucidate the origin of the enantioselectivity.

Highly enantioselective Friedel–Crafts alkylation of N,N-dialkylanilines with trans-β-nitrostyrene catalyzed by a homochiral metal–organic framework

The first enantioselective Friedel–Crafts alkylation of N,N-dialkylanilines with trans-β-nitrostyrene catalyzed by a homochiral MOF afforded the addition products in high yields (∼96%) with excellent ee (∼98%).

Highly efficient asymmetric organocatalytic Friedel-Crafts alkylation of indoles with alpha,beta-unsaturated aldehydes

The development of an improved organocatalyst, N-isopropylated bipyrrolidine 2a, for the asymmetric Friedel-Crafts alkylation of indoles with alpha,beta-unsaturated aldehydes has been presented. The new organocatalyst readily facilitates the enantioselective alkylation reaction, providing 3-alkylated indoles in good to high yields (62-89%) with high levels of enantioselectivity (80-93% ee) using only 2 mol% of catalyst loading.