title: A C-H bond activation-based catalytic approach to tetrasubstituted chiral allenes.
abstract: Enantioselective synthesis of fully substituted allenes has been a challenge due to the non-rigid nature of the axial chirality, which spreads over three carbon atoms. Here we show the commercially available simple Rh complex may catalyse the CMD (concerted metalation/deprotonation)-based reaction of the readily available arenes with sterically congested tertiary propargylic carbonates at ambient temperature affording fully substituted allenes. It is confirmed that the excellent designed regioselectivity for the C-C triple bond insertion is induced by the coordination of the carbonyl group in the directing carbonate group as well as the steric effect of the tertiary O-linked carbon atom. When an optically active carbonate was used, surprisingly high efficiency of chirality transfer was realized, affording fully substituted allenes in excellent enantiomeric excess (ee).
authors.affiliation: Laboratory of Molecular Recognition and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China.
authors.forename: Shangze
authors.initials: S
authors.lastname: Wu
authors.affiliation: Laboratory of Molecular Recognition and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Huang
authors.affiliation: Laboratory of Molecular Recognition and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China.
authors.forename: Wangteng
authors.initials: W
authors.lastname: Wu
authors.affiliation: Laboratory of Molecular Recognition and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China.
authors.forename: Pengbin
authors.initials: P
authors.lastname: Li
authors.affiliation: Laboratory of Molecular Recognition and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China.
authors.forename: Chunling
authors.initials: C
authors.lastname: Fu
authors.affiliation: Laboratory of Molecular Recognition and Synthesis, Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027, China.
authors.forename: Shengming
authors.initials: S
authors.lastname: Ma