Enantioselective difunctionalization of alkenes by a palladium-catalyzed Heck/borylation sequence

Abstract

A palladium catalyzed enantioselective Heck/borylation reaction of alkene-tethered aryl iodides was realized, delivering a variety of 2,3-dihydrobenzofuranyl boronic esters in high yield with excellent enantioselectivity. Asymmetric synthesis of chromane boronic...

Recent Developments in Enantioselective Domino Reactions. Part A: Noble Metal Catalysts

“…Later in 2022, Zhang et al applied another chiral P,N-ligand exhibiting a bulky 3,5-t-Bu 2 -4-OMe-C 6 H 2 group to promote an enantioselective palladium-catalyzed domino Heck/borylation reaction of alkenetethered aryl iodides 97 with B 2 pin 2 . [33] The reaction employed 2.5 mol% of Pd 2 (dba) 3 • CHCl 3 as precatalyst and 7.5 mol% of chiral ligand 75 in diethyl ether as solvent and led at 80 °C to the corresponding chiral bicyclic boronic esters 98 with both moderate to excellent yields (52-98%) and enantioselectivities (53-98% ee), as shown in Scheme 25. The scope of the methodology was found extremely wide since various types of boronic esters could be easily synthesized, spanning from 2,3-dihydrobenzofuranyl boronic esters (X = O, n = 1) to chromane (X = O, n = 2), indane (X = CH 2 , n = 1) and indoline (X = N, n = 1) boronic esters.…”

Palladium‐Catalyzed Intramolecular Dehydrogenative Arylboration of Alkenes

“…[ 11 ] The third strategy could go through oxidative addition to generate carbon‐metal bond, then it would insert into C‐C double bonds to form the ring skeleton (C, Figure 2). [ 12 ] The following transmetalation with B 2 pin 2 (bis(pinacolato)diboron) and further reductive elimination could lead to the desired product. [ 12 ] Although the significant achievements have been established, the novel strategy for constructing valuable complex molecular framework via practical way remains highly demanded.…”

“…[ 12 ] The following transmetalation with B 2 pin 2 (bis(pinacolato)diboron) and further reductive elimination could lead to the desired product. [ 12 ] Although the significant achievements have been established, the novel strategy for constructing valuable complex molecular framework via practical way remains highly demanded. As the significance of boric indole‐fused dihydro‐pyrrole derivatives, we developed the first example about palladium‐catalyzed intramolecular C—H dehydrogenative borylative cyclization reactions to construct such framework (B, Figure 1).…”

An Approach toward 17-Arylsubstituted Marginatafuran-Type Isospongian Diterpenoids via a Palladium-Catalyzed Heck–Suzuki Cascade Reaction of 16-Bromolambertianic Acid

“…Due to the formation of a new chiral quaternary stereocenter, at the first stage as a result of the intramolecular Heck reaction, the products of this domino reaction are formed as a mixture of two diastereomers. Obtaining optically active compounds requires the use of chiral catalysts [26][27][28][29][30]. In the case of lambertianic acid, a reaction with high diastereoselectivity is expected due to the higher steric availability of the α-side of the diterpene core [31].…”