Table 3. Reaction Optimization for 1,3,4-Trifunctionalization of Homoallylmagnesium Bromide—1,4-Boron Migration^a.

			yield (%)
entry	PC	solvent	4a	4a-I	conv (%)
1	Ir(ppy)3	CH3CN	79	4	87
2	Ir(ppy)3	DMSO	<1	33	85
3	Ir(ppy)3	DMF	5	11	91
4	Ir(ppy)3	DMA	2	2	93
5	Eosin Y	CH3CN	76	3	77
6	Rose Bengal	CH3CN	75	4	80
7	Rhodamine B base	CH3CN	79	3	80
8	–	CH3CN	44	16	94
9b	Rhodamine B base	CH3CN	87 (83c)	3	90
10d	–	CH3CN	87	3	95
11e	Rhodamine B base	CH3CN	5	–	57

^aReactions were conducted on a 0.2 mmol scale in the specified solvent (2 mL), conversion (conv) was determined based on recovered bisboryl reagent, and yields were determined by crude GC analysis with n-tetradecane as internal standard.

^bConducted at −20 °C.

^cIsolated yield.

^d365 nm (3 W) at −20 °C.

^eBut-3-enyllithium, in situ generated by lithium/iodine exchange reaction of t-BuLi and 4-iodo-1-butene, used instead of but-3-enylmagnesium bromide, and THF instead of DME as solvent.