Fig. 1: Overview of previous studies and this work.

a Chiral cyclobutanes in natural products and bioactive drugs. b Selective examples to construct cyclobutanes from BCBs. c Asymmetric conjunctive couplings via 1,2-metallate shift. d Asymmetric synthesis of biaryl atropisomers containing cyclobutylboronic esters (this work). ent-4a: enantiomer of 4a.