“…While the photoisomerization by conventional rotation, i. e., the 180 o rotation around the double bond, is regarded to be difficult within the narrow space such as in a crystal or solid-state, the Hula-twist (HT) mechanism, a space-conserving isomerization process, was proposed by Liu et al to explain such the phenomena [13][14][15][16][17]. Not only this hypothesis has sometimes been applied to the numerous examples of E/Z-photoisomerizations in the confined environments [7,[9][10][11][12], but also several investigations have been undertaken to verify this process [18][19][20][21][22]. However, only the 1,2-disubstituted ethylenes were employed in almost all examples previously reported, but, to the best of our knowledge, the tri-and tetra-substituted alkenes have not been used for this type of investigation.…”