Dirhodium(ii)-catalysed cycloisomerization of azaenyne: rapid assembly of centrally and axially chiral isoindazole frameworks

Abstract

Described herein is a dirhodium(II)-catalyzed asymmetric cycloisomerization of azaenyne through a cap-tether synergistic modulation strategy, which represents the first catalytic asymmetric cycloisomerization of azaenyne. This reaction is highly challenging because...

Recent advances in the catalytic asymmetric construction of atropisomers by central-to-axial chirality transfer

“…Very recently, the Zhu group described a rare example of asymmetric cycloisomerization of azaenyne 79 via a cap-tether synergistic modulation method, delivering a series of centrally chiral isoindazole derivatives 80 in excellent yields and enantioselectivities (Scheme 19). 76 Enantioenriched atropisomers 81 could be readily obtained with an external oxidative central-to-axial chirality transfer. This work represents a significant advance in the asymmetric cyclization of conjugated enyne motifs which afforded diverse enantioenriched atropisomers bearing double five-membered heteroaryls.…”

Advances in Atroposelectively De Novo Synthesis of Axially Chiral Heterobiaryl Scaffolds

“…Nevertheless, a series of outstanding strategies to prepare axially chiral biaryls have been developed. These diverse methodologies can be divided into four main categories ( Figure 2 ): (A) atroposelective coupling of two aromatic sub-units [ 33 , 34 , 35 , 36 ], (B) transformation of prochiral heterobiaryl molecules into axially chiral skeletons [ 37 , 38 , 39 , 40 ], (C) central-to-axial chirality conversion [ 41 , 42 , 43 ], and (D) de novo construction of axially chiral molecules [ 44 , 45 , 46 ]. To date, several elegant reviews have been disclosed, in which the authors focused on the atroposelective coupling of two units [ 47 , 48 ], atroposelective transformation of prochiral heterobiaryls [ 11 , 49 , 50 , 51 ], and central-to-axial chirality conversion [ 52 , 53 ].…”

Migratory insertion of copper-allenylidene from propargyl ester

“…It's well known that copper could form both Cu-acetylide species and Cu-carbene easily, which enables the migratory insertion of terminal alkynes onto the carbene carbon. 8 Following our continuous interest in alkyne-based carbene chemistry, 9 we then envisioned that carbene-involved migratory insertion reactions would also be operative for copper-allenylidenes, leading to diverse and useful cumulenes or polyynes (Scheme 1c).…”