Table 1.

Selected optimization conditions for regio- and stereo-controlled 1,2-reductions (see SI for full details)^a

Entry	Ligand	Solv.	T (°C)	Yield of 2 (%)b	ee of 2 (%)c
1	L1	THF	rt	90	50 (S)
2	L2	THF	rt	78	75 (S)
3	L2	THF	−25	87	86 (S)
4	L2	Et2O	−25	83 (98)d	91 (S)
5e	L2	Et2O	−35	n.d.	n.d.
6	L3a	Et2O	−25	96	89 (R)
7	L3b	Et2O	−25	95	91 (R)
8	L3c	Et2O	−25	99	90 (S)
9f	BDP	THF	rt	-	-

^aPerformed on a 0.1 mmol scale in 0.3 mL solvent.

^bBy ¹H NMR using Ph₃CH as internal standard.

^cBy chiral HPLC. Absolute stereochemistry was determined by comparing optical rotation to that of the known compound.

^dIsolated yield (0.25 mmol scale).

^eLow conversion after prolonged reaction time.

^f1,2-/1,4-ratio = 1:7, 60% isolated yield of 1,4-reduced enone.