Organocatalytic diastereo- and atropo-selective construction of eight-membered bridged (hetero)biaryls via asymmetric intramolecular [3 + 2] cycloaddition.

ABSTRACT

An unprecedented and straightforward route for the asymmetric construction of privileged atroposelective bridged (hetero)biaryl eight-membered scaffolds has been accomplished through chiral phosphoric acid catalyzed asymmetric intramolecular [3 + 2] cycloaddition of innovative (hetero)biaryl aldehydes with 3-aminooxindole hydrochlorides. A class of eight-membered bridged (hetero)biaryl lactones fused to spiro[pyrrolidine-oxindole] derivatives, possessing both chiral C-C/C-N axes and multiple contiguous stereocenters, were obtained in good yields with excellent enantioselectivities and diastereoselectivities in one step through this direct strategy. In addition, the good scalability and derivatization of the title compounds demonstrated their synthetic utility.