Chemistry of planar chiral medium-sized heterocycles

Nine-membered E,Z-diallylic heterocycles 1 and [7]-orthocyclphenes 2 exhibit planar chirality at ambient temperature. Their stereochemical stabilities are highly dependent on substituent R1 on the E-Alkene, embedded heteroatom X in the ring, and ring size. Their planar chirality can be transformed into carbon central chirality without loss of enantiopurity. Therefore, they are useful chiral building blocks for biologically active chiral molecules and precursors for chiral reagents. The enantioenriched forms of 1 and 2 are available by optical resolution of racemate, and asymmetric synthesis based on enantioselective cyclization. Planar chiral dialkoxysilane 32 and ketone 33 were also developed.