Development of an SNAr Reaction: A Practical and Scalable Strategy To Sequester and Remove HF

Atroposelective Total Synthesis of Cihunamide B

A short, atroposelective synthesis of cihunamide B (1) is reported. The feature of this report is the decagram-scale SNAr reaction of l-tryptophan derivatives, followed by atroposelective Larock macrocyclization. This strategy allowed the construction of a Trp-Trp cross-linkage with unprecedented atropisomerism. The atroposelectivity of this Larock macrocyclization has been investigated through a combination of experimental and computational chemistry, yielding detailed insights into the synthesis of biaryl linkages. It also enabled the concise synthesis of cihunamide B (1), which is expected to be a potential antibacterial agent.

Palladium-catalyzed enantioselective three-component synthesis of α-arylglycine derivatives from glyoxylic acid, sulfonamides and aryltrifluoroborates

A palladium-catalyzed enantioselective three-component reaction of glyoxylic acid, sulfonamides and aryltrifluoroborates is described. This process provides modular access to the important α-arylglycine motif in moderate to good yields and enantioselectivies. The formed α-arylglycine products constitute useful building blocks for the synthesis of peptides or arylglycine-containing natural products.

Copper-Catalyzed Racemization-Recycle of a Quaternary Center and Optimization Using a Combined Kinetics-DoE/MLR Modeling Approach

The copper-catalyzed racemization of a complex, quaternary center of a key intermediate on route to lanabecestat has been identified. Optimization and mechanistic understanding were achieved through the use of an efficient, combined kinetic-multiple linear regression approach to experimental design and modeling. The use of a definitive screening design with mechanistically relevant factors and a mixture of fitted kinetic descriptors and empirical measurements facilitated the generation of a model that accurately predicted complex reaction time course behavior. The synergistic model was used to minimize the formation of dimer byproducts, determine optimal conditions for batch operation, and highlight superheated conditions that could be accessed in flow, leading to a further increase in yield which was predicted by the original model.