Table 1. Photostationary State Ratios of 2a–d as a Function of Wavelength^a.

wavelength	2a	2b	2c	2d
340 nm	27	51	8	14
365 nm	17	70	3	10
395 nm	3	97	0	<1

^aIrradiation conducted in d₈-THF at −20 °C starting from 2a. PSS ratios measured by ³¹P NMR.