Intermediates capture under various solvent conditions (reaction time: 12 h).

Raw material	HCOOH/H2O (%)	Products
1a	60 : 40	1A + 1b
	50 : 50	1A + 1b
	40 : 60	1A
3a	50 : 50	3A + 3b
	40 : 60	3A + 3b
	30 : 70	3A
5a	40 : 60	5A + 5b
	30 : 70	5A + 5b
	20 : 80	5A