Table 1.

Optimization of halosulfonylation of 1.^[a]

Entry	Substrate	Hal+	Solvent	Yield 3  a or 3  b [%][b]
1	2  a	NIS	THF	41
2	2  a	ICl	THF	49
3	2  a	DIH	THF	78
4	2  a	DID	THF	31
5	2  a	I2	THF	7[c]
6	2  a	DIH	Et2O	quant.
7	2  a	DIH	H2O	99
8	2  a	DIH	CH2Cl2	quant.[d]
9[e]	2  a	DIH	Et2O	nr
10	2  a	DBH	Et2O	9
11	2  a	DBH	Et2O	quant.[d,f]
12	2  a	NBS	Et2O	50[f]
13	2  b	I2	Et2O	91[d,g]
14	2  b	Br2	Et2O	97[d,g]

[a] Optimization carried out on 0.15 mmol scale, with 2.5 equiv sulfinate (1.0 M in H₂O), 1.0 equiv of halogenating agent and 1.0 equiv of 1 (0.75 M in Et₂O). [b] ¹H NMR yields calculated with mesitylene as internal standard. [c] 18 % di‐iodo BCP observed. [d] Isolated yield. [e] Reaction run in the dark. [f] 18 h reaction time after addition of 1. [g] 1.0 equiv of pre‐isolated sulfonyl halide and 1.3 equiv of 1 were reacted in Et₂O for 15 h at rt. X/Hal=Halogen. DXH=dihalohydantoin. DXD=dihalodimedone. NXS=N‐halosuccinimide p‐Tol=para‐tolyl. nr = no reaction.