Table 21.

TiCl₄-promoted rearrangement of (tert-butyldioxy)cyclohexanedienones 472a–d.

Peroxide	Reaction conditions	Quinone	Yield, %
472a	25 °C, 1 h	473a	92
472b	−15 °C, 4 h	473b	98
472c	−78 °C, 0.5 h	473c	93
472d	−78 °C, 0.5 h	473d	91