The formation of benzynes derivatives from ortho-trimethylsilyl triflates using tetra-n-butylammonium fluoride (TBAF) as the benzyne-forming trigger was achieved in a straightforward flow reactor at room temperature. These benzynes were immediately trapped in Diels—Alder reactions to deliver the desired cycloadducts.
Authors:Michael G. Organ, Paul R. Hanson, Alan Rolfe, Thiwanka B. Samarakoon, and Farman Ullah
The generation of stereochemically rich benzothiaoxazepine-1,1´-dioxides for enrichment of high-throughput screening collections is reported. Utilizing a microwave-assisted, continuous-flow organic synthesis platform (MACOS), scale-out of core benzothiaoxazepine-1,1´-dioxide scaffolds has been achieved on multigram scale using an epoxide opening/SNAr cyclization protocol. Diversification of these sultam scaffolds was attained via a microwave-assisted intermolecular SNAr reaction with a variety of amines. Overall, a facile, two-step protocol generated a collection of benzothiaoxazepine-1,1´-dioxides possessing stereochemical complexity in rapid fashion, where all eight stereoisomers were accessed from commercially available starting materials.
Authors:Farman Ullah, Qin Zang, Salim Javed, Aihua Zhou, Christopher A. Knudtson, Danse Bi, Paul R. Hanson, and Michael G. Organ
A microwave-assisted, continuous-flow organic synthesis (MACOS) protocol for the synthesis of functionalized 1,2,5-thiadiazepane 1,1-dioxide library, utilizing a one-pot elimination and inter-/intramolecular double aza-Michael addition strategy is reported. The optimized protocol in MACOS was utilized for scale-out and further extended for library production using a multicapillary flow reactor. A 50-member library of 1,2,5-thiadiazepane 1,1-dioxides was prepared on a 100- to 300-mg scale with overall yields between 50 and 80% and over 90 % purity determined by proton nuclear magnetic resonance (1H-NMR) spectroscopy.