Organic Synthesis and Catalysis
Research Interest
Azaarenes (N-heteroaromatics) and azacycles are among the most frequent motif in drug and drug-like molecules, functional materials, and being considered for Liquid Organic Hydrogen Carriers (LOHCs). Simple azaarene derivatives are synthesized from biomass feedstock. We focus on their regio- and stereoselective functionalization via sustainable catalysis
Phosphite Catalyzed C–H Allylation of Azaarenes via an Enantioselective [2,3]-Aza-Wittig Rearrangement
Angewandte Chemie 131 (40), 14242-14247
A phosphite mediated [2,3]-aza-Wittig rearrangement has been developed for the regio- and enantioselective allylic alkylation of six-membered hetero-aromatic compounds (azaarenes).
Phosphite mediated asymmetric N to C migration for the synthesis of chiral heterocycles from primary amines
Chem. Sci., 2021, 12, 8996
A phosphite mediated stereoretentive C–H alkylation of N-alkylpyridinium salts derived from chiral primary amines was achieved. The reaction proceeds through the activation of the N alkylpyridinium salt substrate with a nucleophilic phosphite catalyst, followed by a base mediated [1,2] aza-Wittig rearrangement and subsequent catalyst dissociation for an overall N to C-2 alkyl migration.
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[1,3]-Claisen Rearrangement via Removable Functional Group Mediated Radical Stabilization
Org. Lett. 2021, 23, 890−895
A thermal O-to-C [1,3]-rearrangement of α-hydroxy acid derived enol ethers was achieved under mild conditions. The 2-aminothiophenol protection of carboxylic acids facilitates formation of the [1,3] precursor and its thermal rearrangement via stabilization of a radical intermediate.
A removable functional group strategy for regiodivergent Wittig rearrangement products.
Org. Biomol. Chem., 2018, 16, 8922
[1,2] and [2,3] Wittig rearrangements are competing reaction pathways, often leading to uncontrollable product distribution. We employ a single removable functional group to fulfill the dual role of attaining a reversible [2,3] and stabilizing radical intermediate for the [1,2] path to obtain both the Wittig products selectively fora broad range of substrates.
