Remote ester groups switch selectivity: diastereodivergent synthesis of tetracyclic spiroindolines.
Stereocontrol in the synthesis of structurally complex molecules, especially those with all-carbon quaternary stereocenters, remains a challenge. Here, we reported the preparation of a class of tetracyclic cyclopenta-fused spiroindoline skeletons through Cu(II)-catalyzed intramolecular [3 + 2] annulation reactions of donor-acceptor cyclopropanes with indoles. Both cis- and trans-diastereomers of tetracyclic spiroindolines are accessed with high selectivities by altering the remote ester groups of cyclopropanes. The origins of this stereocontrol are identified using DFT calculations: attractive interactions between the ester group and arene favor the generation of the trans isomer, while the formation of the cis isomer is preferred when steric repulsions become predominant.
State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China.
Jun
J
Zhu
Yong
Y
Liang
Lijia
L
Wang
Zhong-Bo
ZB
Zheng
K N
KN
Houk
Yong
Y
Tang
D002384:Catalysis; D003300:Copper / Q000737:chemistry; D003521:Cyclopropanes / Q000737:chemistry; D004952:Esters / Q000737:chemistry; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D003521:Cyclopropanes; D004952:Esters; D007211:Indoles; D013141:Spiro Compounds; C057812:indoline; D003300:Copper