Nature Communications

Table 1 Optimization of reaction conditions^a.

From: Synthesis of chiral anti-1,2-diamine derivatives through copper(I)-catalyzed asymmetric α-addition of ketimines to aldimines


Entry	Ligand	Base	T	Yield^b	ee (%)^c
1	(R)-BINAP	Barton’s base	RT	48	−17
2	(R)-Tol-BINAP	Barton’s base	RT	49	−52
3	(R)-SEGPHOS	Barton’s base	RT	50	−20
4	(R)-DTBM-SEGPHOS	Barton’s base	RT	43	−66
5	(R,R)-Ph-BPE	Barton’s base	RT	38	−21
6	(R,R)-QUINOXP*	Barton’s base	RT	55	−31
7	(R)-(S)-JOSIPHOS	Barton’s base	RT	32	0
8	(R,Rp)-TANIAPHOS	Barton’s base	RT	57	86
9	(R,Rp)-TANIAPHOS	Barton’s base	−30	61	96
10	(R,Rp)-TANIAPHOS	TMG	−30	65	96
11	(R,Rp)-TANIAPHOS	Et₃N	−30	75	98
12^d	(R,Rp)-TANIAPHOS	–	−30	77	97
13^d,e	(R,Rp)-TANIAPHOS	–	−30	82	97
14^f	(R,Rp)-TANIAPHOS	–	RT	–	–

DME 1,2-dimethoxyethane, RT room temperature.
^a1a: 0.1 mmol, 2a: 0.15 mmol.
^bDetermined by ¹H NMR analysis of reaction crude mixture using CH₃NO₂ as an internal standard.
^cDetermined by chiral-stationary-phase HPLC analysis.
^dIn total, 5 mol % mesitylcopper and 5 mol % ligand were used.
^eDME was employed instead of THF.
^fThe reaction was performed without mesitylcopper and ligand.

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