10 Circularly Polarized Luminescence (CPL) Based on Planar …
365
Fig. 10.28 Synthesis of one-handed double helical molecule
Pd 2 (dba) 3 /P
t Bu 3 /CuI afforded the diyne 59 selectively, as shown in Fig. 10.28.
The coupling reaction between 59 with triisopropylsilyl (TIPS) acetylene using a
Pd 2 (dba) 3 /dppf catalyst system enabled us to obtain the corresponding tetrayne 60.
K 2 CO 3 /MeOH allowed the chemoselective removal of the TMS group from 60 to
obtain diyne 61. Then, Sonogashira-Hagihara coupling of 60 with p-iodoanisole
produced 62. The TIPS group was easily removed by Bu 4 NF, and the reaction with mdiiodobenzene provided enantiopure cyclic molecule 63 consisting of two optically
active cyclophanes, in which boomerang-shaped arylene-ethynylene containing five
benzene rings are stacked at the second and fourth phenylene moieties. This cyclic
molecule forms a one-handed double helical structure; for example, the (R p ,R p )isomer construct left-handed double helices. This double helical molecule also
emitted intense CPL with Φ PL of 0.62 and |g lum | = 1.6 × 10
−3 ; the PL and CPL
spectra are shown in Fig. 10.29.
Enantiopure bisphenol 57 was reacted with K 2 CO 3 and MeI to obtain a new
chiral building block (R p )-64 in high yield (Fig. 10.30) (Kikuchi et al. 2019). The
reaction of (R p )-64 with TMS acetylene in the presence of Pd 2 (dba) 3 /P
t Bu 3 /CuI
365
Fig. 10.28 Synthesis of one-handed double helical molecule
Pd 2 (dba) 3 /P
t Bu 3 /CuI afforded the diyne 59 selectively, as shown in Fig. 10.28.
The coupling reaction between 59 with triisopropylsilyl (TIPS) acetylene using a
Pd 2 (dba) 3 /dppf catalyst system enabled us to obtain the corresponding tetrayne 60.
K 2 CO 3 /MeOH allowed the chemoselective removal of the TMS group from 60 to
obtain diyne 61. Then, Sonogashira-Hagihara coupling of 60 with p-iodoanisole
produced 62. The TIPS group was easily removed by Bu 4 NF, and the reaction with mdiiodobenzene provided enantiopure cyclic molecule 63 consisting of two optically
active cyclophanes, in which boomerang-shaped arylene-ethynylene containing five
benzene rings are stacked at the second and fourth phenylene moieties. This cyclic
molecule forms a one-handed double helical structure; for example, the (R p ,R p )isomer construct left-handed double helices. This double helical molecule also
emitted intense CPL with Φ PL of 0.62 and |g lum | = 1.6 × 10
−3 ; the PL and CPL
spectra are shown in Fig. 10.29.
Enantiopure bisphenol 57 was reacted with K 2 CO 3 and MeI to obtain a new
chiral building block (R p )-64 in high yield (Fig. 10.30) (Kikuchi et al. 2019). The
reaction of (R p )-64 with TMS acetylene in the presence of Pd 2 (dba) 3 /P
t Bu 3 /CuI