A broader range of aldehydes was then investigated (Scheme 2c). Benzaldehyde itself gave good yield of combined mono and di-functionalized products (73% 13a, mono:di 1.3:1). 2,3-Dimethyl and 2,4-dimethyl benzaldehydes reacted to give 14a and 15a in moderate to good yields. Benzyl protected phenol was tolerated, as was an O-allyl substituent, a challenging substrate in a palladium mediated process due to allylic activation. 2-Phenylbenzaldehyde, 2-napthaldehyde and 6-methoxy-2napthaldehyde were particularly effective, giving 18a, 19a and 20a in 87%, 96% and 71% yield respectively. Halogenated examples were tolerated without cross-coupling occurring. In substrates possessing additional potential directing sites (23a-28a), C-H sulfonylation was only observed at the position ortho to the aldehyde due to the superior directing ability of the transient directing group. Ester 23a was tolerated without any observed hydrolysis. Amide-containing 24a and benzyl alcohol containing 25a were prepared in 48% and 51% yield respectively. The presence of a coordinating sulfonamide group at the 3-position gave exclusive sulfonylation at the most hindered 2-position (26a) indicating a tertiary directing effect of the NHSO2Me group. The Cu-mediated conditions also gave sulfonylated pyridine-4carboxaldehyde and 2-methoxypyridine-4-carboxaldehyde (27a, 28a). A substrate derived from estrone underwent preferential sulfonylation reaction adjacent to the aldehyde functional group in the presence of the ketone (29a), using the aldehyde as the limiting reagent. The reaction of 9-phenanthene carboxaldehyde gave peri-sulfonylated product 30a exclusively, favoring the required [6,6]-cupracyclic intermediate over the potential ortho-sulfonylation. In the case of 1-napthaldehyde, perifunctionalization was again the major product in a 2:1 ratio with the less hindered ortho-product. On blocking the ortho-position with a methyl group, reduced peri-reactivity was observed. Scheme 2. Reaction scope varying the sulfinate salt and aldehyde. Reactions performed on 0.2 mmol scale. Isolated yields reported. a 22 h reaction time.