Table 1.

Substrate scope of squaramide catalyzed MAC addition reactions^a

entry	enone	R3	product	temp (°c)	time (h)	yieldc (%)	eed (%)	entry	enone	R3	product	temp (°C)	time (h)	yieldc (%)	eed (%)
1		MOM TBS	3a 5a	–30 –20	24 36	98 96	97 96	10		MOM TBS	3j 5j	–10 0	28 48	98 96	95 94
2		MOM	3b	–30	20	98	97	11		MOM	3k	23	24	97	88
3		MOM	3c	–30	24	98	97	12		MOM	3l	23	24	96	92
4		MOM TBS	3d 5d	0 0	28 72	99 96	92 90	13e		MOM	3m	–10	72	96	89
5		MOM TBS	3e 5e	–30 –20	24 36	99 95	98 97	14		MOM TBS	3n 5n	–30 –20	20 36	96 98	96 94
6		TBS	5f	0	24	93	90	15		MOM	3o	–30	28	96	97
7		TBS	5g	–10	48	94	90	16		MOM TBS	3p 5p	–30 –20	24 36	98 92	96 94
8		MOM	3h	–30	30	98	91	17		MOM	3q	23	24	94	89
								18		MOM	3r	–30	24	98	97
9		MOM TBS	3i 5i	0 0	36 72	97 90	92 89	19		MOM TBS	3s 5s	–30 –20	24 36	99 93	94 85

^aConditions: Reactions performed with 1 (0.36 mmol), 2 or 4 (0.30 mmol), VIc (5 mol %), CH₂Cl₂ (0.6 mL).

^cIsolated yield.

^dEnantiomeric excess determined by chiral stationary phase HPLC.

^e4Å MS were used as an additive to avoid hydrolysis.