Design and synthesis of planar chiral heterocyclic carbene precursors derived from [2.2]paracyclophane.
A unique family of planar chiral symmetrical N-heterocyclic carbene precursors with restricted flexibility derived from [2.2]paracyclopane were obtained by a new synthetic route. The resolution of 4-amino-13-bromo[2.2]paracyclophane was achieved with relatively high efficiency. Starting from (4 S p,13 R p)-4-amino-13-bromo[2.2]paracyclophane, the planar chiral pseudogem-disubstituted [2.2]paracyclophanyl dihydroimidazoliums were prepared in a four-step sequence with good yields. The resulting dihydroimidazolium salts were fully characterized with a series of methods including single-crystal X-ray diffraction technique.
Duan
Wenzeng
W
Department of Chemistry, Shandong University, Shanda South Road No. 27, Jinan, People's Republic of China.
Ma
Yudao
Y
Xia
Houqi
H
Liu
Xueying
X
Ma
Qingshuang
Q
Sun
Junshan
J