Copper‐Catalyzed Highly Selective Protoboration of CF₃‐Containing 1,3‐Dienes

Abstract

The copper-catalyzed highly selective protoboration of CF 3 -containing conjugated diene with proton source and B 2 Pin 2 has been developed. This chemistry could suppress the well-known defluorination and provideb orated reagents with an intact CF 3 -group.F urther studies indicated that the functional group tolerance of this chemistry is very well, and the products could be used as versatile precursors for different types of transformations.I mportantly,u sing chiral diphosphine ligand, we have developed the first example for using such starting material to synthesis allylic boron-reagents which bearing aC F 3 -containing chiral center.N otably,t he reaction mechanism was intensively studied by DFT calculations,which could reveal the reason that defluorination was inhibited.

Palladium‐Catalyzed Intramolecular Dehydrogenative Arylboration of Alkenes

“…Recently, Engel, He, Chen, Peng and coworkers developed the elegant carboboration of alkene to install indole motif and boron ester group into C‐C double bonds, [ 6 ] but developing novel reaction system to well tolerate substituted indole derivates is still challenging. Following our research interest in the synthesis of indole‐fused compounds [ 7 ] and selective boronation, [ 8 ] we developed a practical oxidative borylative cyclization reaction to construct borylative indole‐fused dihydro‐ pyrrole framework with good functional group tolerance (B, Figure 1). Importantly, the enantioselectivity for constructing the quaternary carbon chiral center could be controlled by employing chiral ligand.…”

Cu-Catalyzed Enantioselective Protoboration of 2,3-Disubstituted 1,3-Dienes

“…Mechanistic investigations were consistent with borocupration being both rate- and enantio-determining and with protonation occurring via an S E 2-type mechanism. Of note, a handful of Cu-catalyzed enantioselective protoborations using electronically biased conjugated dienes has also been reported (i.e., 1,2-dihydropyridines, [ n ]­dendralenes, trifluoromethylated linear 1,3-dienes) …”

“…Of note, a handful of Cu-catalyzed enantioselective protoborations using electronically biased conjugated dienes has also been reported (i.e., 1,2-dihydropyridines, [ n ]dendralenes, trifluoromethylated linear 1,3-dienes). 5 …”

Asymmetric construction of allylicstereogenic carbon center featuring atrifluoromethyl group via enantioselective reductive fluoroalkylation

“…It is worth mentioning that Shibata reported the asymmetric introduction of nucleophilic trifluoromethyl group onto allylic site via (DHQD) 2 PHAL-catalzyed kinetic resolution of electron-deficient allyl fluorides 56 . Apart from the direct nucleophilic trifluoromethylation, with the usage of CF 3preinstalled 1,3-dienes or enones, copper-catalyzed enantioselective protoboration and hydroxytetraphenylene-catalyzed asymmetric conjugate addition of vinyl boronic acids were demonstrated by Zhang 57 and Chang 58 respectively (Fig. 1c).…”