Palladium‐Catalyzed Asymmetric Intramolecular Reductive Heck Desymmetrization of Cyclopentenes: Access to Chiral Bicyclo[3.2.1]octanes

Abstract

Ap alladium-catalyzed asymmetric reductive Heck reaction of unactivated aliphatic alkenes,w ith eliminable b-hydrogen atoms,h as been realized for the first time.A series of optically active bicyclo[3.2.1]octanes bearing chiral quaternary and tertiary carbon stereocenters were obtained in good yields with excellent enantioselectivities,e xhibiting good functional-group tolerance and scalability.M oreover,d euterated optically active bicyclo[3.2.1]octanes were also obtained in high efficiency.

Recent Advances of Catalytic Enantioselective Heck Reactions and Reductive‐Heck Reactions

“…As shown in Scheme 59, the reaction catalyzed by Pd(OAc) 2 /( S )‐Diflurophos complex afforded chiral bicyclo[3.2.1]octanes in excellent yields and ees. [ 71 ] Other diphosphine ligands, such as BINAP, SEGPHOS, and Diflurophos, could also suppress the β‐hydride elimination of alkyl‐Pd intermediate, albeit with inferior ees.…”

Synthesis and crystal structure of tert-butyl 1-(2-iodobenzoyl)cyclopent-3-ene-1-carboxylate

“…1-(2-Iodobenzoyl)cyclopent-3-ene-1-carboxylates were recently employed as novel substrates to construct bicyclo[3.2.1]octanes that are widely found in natural products and bioactive molecules with antibacterial and antithrombotic activities (Yuan et al, 2019). Although the authors carried out some control experiments to reveal the reaction mechanism, crystal structures of the substrates have not been reported yet.…”

“…The title compound was prepared according to a general literature protocol (Yuan et al, 2019). 1 H NMR (300 MHz, CDCl 3 ): 8.0 (dd, J = 7.9, 1.2 Hz, 1H), 7.4 (dd, J = 7.8, 1.8 Hz, 1H), 7.3 (td, J = 7.5, 1.2 Hz, 1H), 7.1 (td, J = 7.8, 1.8 Hz, 1H), 5.6 (s, 2H), 3.1 (s, 4H), 1.2 (s, 9H).…”

Pd-Catalyzed Enantioselective Tandem C–C Bond Activation/Cacchi Reaction between Cyclobutanones and o-Ethynylanilines

“…1 Intramolecular enantioselective carbopalladation of 1,1-disubstituted C−C double bond represents an elegant approach to generating chiral σ-alkylpalladium species, which can be in situ trapped by various nucleophiles such as cyanide, azole, and hydride as reported by the groups of Zhu, 2−7 Lautens, 8 Jia, 9−11 Diaz, 12 Zhou, 13,14 Tong, 15,16 Zhang, 17−20 Lu, 21 and Lin and Yao (Scheme 1a). 22,23 Transition-metal catalyzed C−C σ-bond activation has received considerable attention in the past decade. 24−29 Owing to the inherent high ring strain, C−C σ-bond of cyclobutanones can be easily cleaved, and Rh-and Ni-catalyzed enantioselective C−C bond activation of prochiral cyclobutanones has been established by the groups of Murakami, 30−32 Cramer, 33−35 and Dong.…”