Total synthesis of biselide A.

A total synthesis of the marine macrolide biselide A is described that relies on an enantiomerically enriched α-chloroaldehyde as the sole chiral building block. Several strategies to construct the macrocycle are presented including a macrocyclic Reformatsky reaction that ultimately provides access to the natural product in a longest linear sequence of 18 steps. Biological testing of synthetic biselide A suggests this macrolide disrupts cell division through a mechanism related to the regulation of microtubule cytoskeleton organization. Overall, this concise synthesis and insight gained into the mechanism of action should inspire medicinal chemistry efforts directed at structurally related anticancer marine macrolides.

A convenient photocatalytic fluorination of unactivated C-H bonds.

Fluorination reactions are essential to modern medicinal chemistry, thus providing a means to block site-selective metabolic degradation of drugs and access radiotracers for positron emission tomography imaging. Despite current sophistication in fluorination reagents and processes, the fluorination of unactivated CH bonds remains a significant challenge. Reported herein is a convenient and economic process for direct fluorination of unactivated CH bonds that exploits the hydrogen abstracting ability of a decatungstate photocatalyst in combination with the mild fluorine atom transfer reagent N-fluorobenzenesulfonimide. This operationally straightforward reaction provides direct access to a wide range of fluorinated organic molecules, including structurally complex natural products, acyl fluorides, and fluorinated amino acid derivatives.

Copper-catalyzed amination of primary benzylic C-H bonds with primary and secondary sulfonamides.

A room-temperature, copper-catalyzed amination of primary benzylic C-H bonds with primary and secondary sulfonamides is described. The reaction is applicable to the coupling of a range of primary and secondary benzylic hydrocarbons with a diverse set of sulfonamides and is tolerant of substitution on both coupling partners. Factors which influence the selectivity of C-H functionalization between primary and secondary sites are examined.