Requirements for Selective Hydrophobic Acceleration in the Reduction of Ketones
摘要:
Reductions of various quaternized hydrophobic beta-keto amines were performed in water and in methanol using borohydride anions carrying hydrophobic groups. The most important requirement of the substrate to permit hydrophobically accelerated selective reductions is the ability of the hydrophobic group of the substrate and its attached keto group to attain a coplanar relationship. Some derivatives of naturally occurring steroid diones have also been employed as substrates to probe the mechanism and utility of these hydrophobically accelerated selective reductions further.
C–H Functionalization-Enabled 11-Step Semisynthesis of (−)-Veragranine A and Characterization of Synthetic Analogs in Osteoarthritis-related Pain Treatment
作者:Donghui Ma、Paz Duran、Reem Al-Ahmad、Sara Hestehave、Margarita Joa、Omar Alsbiei、Erick J. Rodríguez-Palma、Yanrong Li、Shilin Wang、Rajesh Khanna、Mingji Dai
DOI:10.1021/jacs.4c04025
日期:2024.6.19
the cholestane steroidal alkaloid (−)-veragranine A with a 6/6/6/5/6/6 hexacyclic ring system, eight stereocenters, and a unique C12–C23 linkage. Our synthesis features a Schönecker–Baran C–H oxidation at C12, a Suzuki–Miyaura cross-coupling to form the C12–C23 bond, and a hydrogen atom transfer (HAT)-initiated Minisci C–H cyclization to forge the C20–C22 bond with desired stereochemistry at C20. These