Nature Communications

Table 1 Screening of NHC for enantioselective cross-hydroalkenylation^a.

From: NHC-Ni catalyzed enantioselective synthesis of 1,4-dienes by cross-hydroalkenylation of cyclic 1,3-dienes and heterosubstituted terminal olefins


Entry	L	1	R¹/R²	3	Yield %	3:4	% ee 3
1	L1	1a	H/OTES	3aa	>95	95:5	78^c
2	L2	1a	H/OTES	3aa	36	95:5	54^c
3	L3	1a	H/OTES	3aa	>95	95:5	87^c
4	L3	1b	H/n-Oct	3ba	>95	95:5	6^c
5	L3	1c	H/OTMS	3ca	>95	80:20	75^c
6	L3	1d	OTES/H	3da	>95	71:29	48
7	L3	1e	OMe/H	3ea	84	75:25	39
8^b	L3	1 f	OTIPS/H	3fa	78	82:18	29
9	L3	1 g	Me/OTES	3ga	>95	68:32	92; 98^d
10	L3	1 h	Me/OTMS	3 ha	>95	75:25	86
11	L2	1i	OTES/Me	3ia	>95	>95:5	90
12	L3	1i	OTES/Me	3ia	>95	>95:5	96

^aGeneral reaction condition: cyclic 1,3-diene 1 and heterosubstituted terminal olefin 2 were added to the indicated catalyst and stirred at r.t. for 6 h. Yields and selectivity were determined by ¹H NMR, HPLC, and isolation. Product with –ve optical rotation was obtained.
^b24 h.
^c+ve optical rotation value was obtained (see Fig. 5).
^dee of chiral 1,4-diene 4.

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