Table 1. Catalyst/reagent screening.

Entry	Substrates (equiv.)	Conditionsa	Yield 3ab (%)
1	1a (1), 2a (2)	5 mol% Rh(cod)2 BF4/BINAP	n.d.c
2	1a (1), 2a (5)	15 mol% CoCp(CO)2	n.d.
3	1a (1), 2a (3)	10 mol% CoCl2, 10 mol% dppe 20 mol% Zn	n.d.
4	1a (1), 2a (1.5)	10 mol% Ni(cod)2, 20 mol% SIPr	n.d.
5	1a (1), 2a (1.5)	10 mol% Ni(cod)2, 20 mol% IMes	n.d.
6	1a (1), 2a (1.5)	10 mol% Ni(cod)2, 10 mol% Xantphos	n.d.
7	1a (1), 2a (1.5)	2 mol% Cp*RuCl(cod)	n.d.
8	1a (1), 2a (3)	2 mol% [Ir(cod)Cl]2, 4 mol% DPPF	Trace
9	1a (1), 2a (3)	1.2 equiv. NbCl5	n.d.
10	1a (1), 2a (3)	5 mol% Ph3PAuOPOF2	n.d.
11	1a (1), 2a (3)	5 mol% AuCl3, 1.1 equiv. MsOH	n.d.
12	1a (1), 2a (3)	5 mol% AuPEt3Cl, 5 mol% AgSbF6	n.d.
13	1a (1), 2a (3)	10 mol% AgOTf, 10 mol% CuBr	n.d.
14	1a (1), 2a (3)	10 mol% FeI2, 20 mol% dppp 20 mol% Zn	n.d.
15	1a (1), 2a (3)	10 mol% FeI2, 20 mol% dppp 20 mol% Zn, 20 mol% ZnI2	n.d.
16	1a (1), 2a (2)	20 mol% Fe(OAc)2, 40 mol% Zn, 26 mol% p-OMe,iPrPDAIm	Trace
17	1a (1), 2a (2)	10 mol% FeCl2, 20 mol% MesPDAI 20 mol% Zn	16d

^aDetailed conditions available in ESI or ref. 20.

^bDetected by GC/MS.

^cn.d. = not detected.

^dNMR yield.