Asymmetric [3+2] Annulations of 1,4-Di-thiane-2,5-diol and N-Boc Aldimines Catalyzed by Tertiary-amine Thiourea†

doi:10.7503/cjcu20170847

Abstract

Abstract:

A highly enantioselective asymmetric [3+2] annulation of 1,4-di-thiane-2,5-diol and N-tert-butoxy-carbonyl(N-Boc) aldimines was catalyzed by a bifunctional tertiary-amine thiourea catalyst. The N-Boc aldimine was assumed to be activated and oriented by the hydrogen bonds of the thiourea, meanwhile the tertiary amine of the catalyst would provide suitable basicity to enhance the nucleophilicity of the mercaptoace-taldehyde. This method realized the construction of double chiral center via a one-step synthesis. As a result, a number of chiral thiazolidine scaffolds, which present in bioactive molecules widely, were smoothly synthesized with 10%(molar fraction) chiral catalysts, and achieved up to 95% enantioselectivity and 7:1 diastereoselectivity in good yields.

Key words: 3+2] Annulation, Thiazolidine, Tertiary amine thiourea, Organocatalysis

CLC Number:

O626.25

TrendMD:

DONG Xu, FENG Boxu, CHEN Li, LI Xin. Asymmetric [3+2] Annulations of 1,4-Di-thiane-2,5-diol and N-Boc Aldimines Catalyzed by Tertiary-amine Thiourea^†[J]. Chem. J. Chinese Universities, 2018, 39(8): 1707.

Figures/Tables 8

Scheme 1 Selected bioactive thiazolidine derivatives

Scheme 2 Enantioselective synthesis of substituted phenyl-thiazolidine catalyzed by tertiary-amine thiourea

Table 1 Appearance, optical rotation, yields and HRMS data of compounds 3a—3m

Compd.	Appearance	[α $] D 20$ (c 1.00, CHCl₃)	Yield(%)	HRMS(calcd.), m/z[M+Na]⁺
3a	Colorless oil	-20.6	96	304.0983(304.0975)
3b	Colorless oil	-12.5	95	318.1140(318.1134)
3c	Colorless oil	-15.3	93	318.1140(318.1133)
3d	Colorless oil	-9.6	82	338.0594(338.0588)
3e	Colorless oil	-9.8	91	382.0088(382.0077)
3f	Yellow oil	-9.2	91	372.0857(372.0853)
3g	Colorless oil	-16.3	95	334.1089(334.1087)
3h	Colorless oil	-17.8	88	318.1140(318.1130)
3i	White oil	-27.3	85	338.0594(338.0585)
3j	White oil	-13.5	93	382.0088(382.0083)
3k	Colorless oil	-14.9	90	338.0594(338.0585)
3l	Colorless oil	-17.1	94	346.1453(346.1447)
3m	White oil	-41.7	95	354.1140(354.1148)

Table 1 Appearance, optical rotation, yields and HRMS data of compounds 3a—3m

Compd.	Appearance	[α $] D 20$ (c 1.00, CHCl₃)	Yield(%)	HRMS(calcd.), m/z[M+Na]⁺
3a	Colorless oil	-20.6	96	304.0983(304.0975)
3b	Colorless oil	-12.5	95	318.1140(318.1134)
3c	Colorless oil	-15.3	93	318.1140(318.1133)
3d	Colorless oil	-9.6	82	338.0594(338.0588)
3e	Colorless oil	-9.8	91	382.0088(382.0077)
3f	Yellow oil	-9.2	91	372.0857(372.0853)
3g	Colorless oil	-16.3	95	334.1089(334.1087)
3h	Colorless oil	-17.8	88	318.1140(318.1130)
3i	White oil	-27.3	85	338.0594(338.0585)
3j	White oil	-13.5	93	382.0088(382.0083)
3k	Colorless oil	-14.9	90	338.0594(338.0585)
3l	Colorless oil	-17.1	94	346.1453(346.1447)
3m	White oil	-41.7	95	354.1140(354.1148)

Table 2 1H NMR and 13C NMR data of compounds 3a—3m*

Compd.	¹H NMR(400 MHz), δ	¹³C NMR(100 MHz), δ
3a	7.44(dd, J=7.2, 1.9 Hz, 2H), 7.32(dd, J=8.2, 6.4 Hz, 2H), 7.28—7.25(m, 1H), 6.00(s, 1H), 5.86(s, 1H), 4.18(s, 1H), 3.29(dd, J=12.0, 4.9 Hz, 1H), 3.09(dd, J=12.0, 3.3 Hz, 1H), 1.19(s, 9H)	153.37, 141.80, 128.34, 127.73, 126.40, 84.59, 81.49, 65.02, 36.84, 27.98
3b	7.44(d, J=8.1 Hz, 2H), 7.12(d, J=7.6 Hz, 2H), 6.04(s, 1H), 5.92(s, 1H), 5.26(d, J=4.5 Hz, 1H), 3.32(dd, J=11.7, 4.7 Hz, 1H), 2.98(dd, J=11.8, 2.2 Hz, 1H), 2.30(s, 3H),1.23(s, 9H)	152.54, 139.72, 136.79, 128.48, 126.99, 83.96, 79.93, 64.79, 37.75, 27.39, 20.23
Compd.	¹H NMR(400 MHz), δ	¹³C NMR(100 MHz), δ
3c	7.37(s, 1H), 7.35(s, 1H), 7.19(t, J=7.9 Hz, 1H), 7.06(d, J=7.2 Hz, 1H), 6.04(s, 1H), 5.90(s, 1H), 5.28(d, J=4.5 Hz, 1H), 3.32(dd, J=11.7, 4.7 Hz, 1H), 2.99(dd, J=11.7, 2.2 Hz, 1H), 2.31(s, 3H), 1.21(s, 9H)	153.45, 143.49, 138.16, 128.85, 128.73, 128.50, 125.00, 84.86, 80.85, 65.88, 38.73, 28.27, 21.46
3d	7.67(d, J=2.0 Hz, 1H), 7.50(d, J=7.5 Hz, 1H), 7.37—7.25(m, 1H), 6.09(s, 1H), 5.95(s, 1H), 5.49(d, J=4.4 Hz, 1H), 3.36(dd, J=11.7, 4.7 Hz, 1H), 3.02(dd, J=11.7, 2.0 Hz, 1H), 1.23(s, 9H)	153.20, 146.28, 134.29, 130.51, 128.26, 127.99, 126.58, 84.70, 81.18, 65.19, 38.97, 28.28
3e	7.82(s, 1H), 7.56(d, J=7.8 Hz, 1H), 7.44(d, J=8.1 Hz, 1H), 7.28(t, J=7.9 Hz, 1H), 6.09(s, 1H), 5.94(s, 1H), 5.52(d, J=4.3 Hz, 1H), 3.36(dd, J=11.7, 4.7 Hz, 1H), 3.02(d, J=11.7 Hz, 1H), 1.23(s, 9H)	152.27, 145.60, 130.31, 130.07, 129.92, 126.13, 121.55, 83.77, 80.27, 64.23, 38.08, 27.37
3f	7.70(m, 2H), 7.54(d, J=7.8 Hz, 1H), 7.46(t, J=7.7 Hz, 1H), 6.06(s, 1H), 5.88(s, 1H),4.35(s, 1H), 3.33(dd, J=12.0, 4.9 Hz, 1H), 3.10(dd, J=12.0, 2.9 Hz, 1H), 1.18(s, 9H)	153.08, 143.11, 130.09, 128.98, 125.35, 124.63, 123.67, 122.64, 84.44, 81.93, 64.56, 37.10, 27.92
3g	7.25—7.18(m, 2H), 7.10(dt, J=7.7, 1.2 Hz, 1H), 6.81(dd, J=8.1, 2.7 Hz, 1H), 6.05(q, J=3.8 Hz, 1H), 5.93(s, 1H), 5.36(s, 3H), 3.77(s, 1H), 3.33(dd, J=11.7, 4.8 Hz, 1H), 3.00(dd, J=11.6, 2.4 Hz, 1H), 1.22(s, 9H)	160.61, 153.41, 145.32, 129.76, 120.05, 113.77, 113.24, 84.85, 80.93, 65.76, 55.48, 38.66, 28.30
3h	7.75(dd, J=7.3, 1.5 Hz, 1H), 7.22—7.04(m, 3H), 6.15(s, 1H), 6.03(s, 1H), 5.31(s, 1H), 3.36(dd, J=11.8, 4.8 Hz, 1H), 2.98(dd, J=11.8, 3.0 Hz, 1H), 2.36(s, 3H), 1.17(s, 9H)	153.43, 141.57, 135.09, 130.61, 127.92, 126.98, 126.92, 85.09, 80.82, 62.47, 38.06, 28.20, 19.28
3i	7.67(d, J=7.7 Hz, 1H), 7.35(d, J=7.9 Hz, 1H), 7.32—7.18(m, 2H), 6.24(s, 1H), 5.97(s, 1H), 4.34(s, 1H), 3.30(dd, J=12.2, 5.4 Hz, 1H), 3.07(dd, J=12.2, 5.1 Hz, 1H), 1.24(s, 9H)	153.29, 139.38, 132.00, 129.30, 128.71, 127.10, 85.14, 81.67, 61.60, 35.44, 29.69, 27.94
3j	7.68(d, J=7.7 Hz, 1H), 7.54(dd, J=8.0, 3.3 Hz, 1H), 7.41—7.27(m, 1H), 7.15(d, J=6.4 Hz, 1H), 6.20(s, 1H), 5.98(t, J=4.9 Hz, 1H), 4.35(s, 1H), 3.38—3.21(m, 1H), 3.15—3.02(m, 1H), 1.25(s, 9H)	153.32, 140.90, 132.62, 129.01, 127.77, 127.21, 122.11, 85.33, 81.71, 64.39, 35.34, 27.99
3k	7.60(d, J=8.5 Hz, 2H), 7.35(d, J=8.1 Hz, 2H), 6.08(s, 1H), 5.95(s, 1H), 5.42(d, J=4.3 Hz, 1H), 3.35(dd, J=11.7, 4.7 Hz, 1H), 3.01(dd, J=11.7, 2.1 Hz, 1H), 1.23(s, 9H)	152.31, 141.94, 132.51, 128.89, 127.96, 83.81, 80.18, 64.22, 37.98, 27.37
3l	7.48(d, J=8.2 Hz, 2H), 7.19(d, J=8.1 Hz, 2H), 6.04(s, 1H), 5.92(s, 1H), 5.27(d, J=4.4 Hz, 1H), 3.32(dd, J=11.7, 4.7 Hz, 1H), 2.99(dd, J=11.7, 2.3 Hz, 1H), 2.94—2.77(m, 1H), 1.22(d, J=6.9 Hz, 6H), 1.18(s, 9H)	152.55, 147.94, 140.04, 127.08, 125.83, 83.94, 79.93, 64.78, 37.78, 33.66, 27.38, 23.49
3m	8.16(d, J=8.4 Hz, 1H), 7.96(dd, J=8.1, 1.7 Hz, 2H), 7.85(d, J=8.2 Hz, 1H), 7.68—7.45(m, 3H), 6.84(s, 1H), 6.17(s, 1H), 5.46(s, 1H), 3.46(dd, J=11.9, 5.1 Hz, 1H), 3.08—3.00(m, 1H), 1.10(s, 9H)	152.73, 137.97, 133.78, 130.29, 128.74, 127.75, 126.07, 125.59, 125.34, 123.13, 122.92, 84.59, 80.03, 61.66, 37.27, 27.36

Table 2 1H NMR and 13C NMR data of compounds 3a—3m*

Compd.	¹H NMR(400 MHz), δ	¹³C NMR(100 MHz), δ
3a	7.44(dd, J=7.2, 1.9 Hz, 2H), 7.32(dd, J=8.2, 6.4 Hz, 2H), 7.28—7.25(m, 1H), 6.00(s, 1H), 5.86(s, 1H), 4.18(s, 1H), 3.29(dd, J=12.0, 4.9 Hz, 1H), 3.09(dd, J=12.0, 3.3 Hz, 1H), 1.19(s, 9H)	153.37, 141.80, 128.34, 127.73, 126.40, 84.59, 81.49, 65.02, 36.84, 27.98
3b	7.44(d, J=8.1 Hz, 2H), 7.12(d, J=7.6 Hz, 2H), 6.04(s, 1H), 5.92(s, 1H), 5.26(d, J=4.5 Hz, 1H), 3.32(dd, J=11.7, 4.7 Hz, 1H), 2.98(dd, J=11.8, 2.2 Hz, 1H), 2.30(s, 3H),1.23(s, 9H)	152.54, 139.72, 136.79, 128.48, 126.99, 83.96, 79.93, 64.79, 37.75, 27.39, 20.23
Compd.	¹H NMR(400 MHz), δ	¹³C NMR(100 MHz), δ
3c	7.37(s, 1H), 7.35(s, 1H), 7.19(t, J=7.9 Hz, 1H), 7.06(d, J=7.2 Hz, 1H), 6.04(s, 1H), 5.90(s, 1H), 5.28(d, J=4.5 Hz, 1H), 3.32(dd, J=11.7, 4.7 Hz, 1H), 2.99(dd, J=11.7, 2.2 Hz, 1H), 2.31(s, 3H), 1.21(s, 9H)	153.45, 143.49, 138.16, 128.85, 128.73, 128.50, 125.00, 84.86, 80.85, 65.88, 38.73, 28.27, 21.46
3d	7.67(d, J=2.0 Hz, 1H), 7.50(d, J=7.5 Hz, 1H), 7.37—7.25(m, 1H), 6.09(s, 1H), 5.95(s, 1H), 5.49(d, J=4.4 Hz, 1H), 3.36(dd, J=11.7, 4.7 Hz, 1H), 3.02(dd, J=11.7, 2.0 Hz, 1H), 1.23(s, 9H)	153.20, 146.28, 134.29, 130.51, 128.26, 127.99, 126.58, 84.70, 81.18, 65.19, 38.97, 28.28
3e	7.82(s, 1H), 7.56(d, J=7.8 Hz, 1H), 7.44(d, J=8.1 Hz, 1H), 7.28(t, J=7.9 Hz, 1H), 6.09(s, 1H), 5.94(s, 1H), 5.52(d, J=4.3 Hz, 1H), 3.36(dd, J=11.7, 4.7 Hz, 1H), 3.02(d, J=11.7 Hz, 1H), 1.23(s, 9H)	152.27, 145.60, 130.31, 130.07, 129.92, 126.13, 121.55, 83.77, 80.27, 64.23, 38.08, 27.37
3f	7.70(m, 2H), 7.54(d, J=7.8 Hz, 1H), 7.46(t, J=7.7 Hz, 1H), 6.06(s, 1H), 5.88(s, 1H),4.35(s, 1H), 3.33(dd, J=12.0, 4.9 Hz, 1H), 3.10(dd, J=12.0, 2.9 Hz, 1H), 1.18(s, 9H)	153.08, 143.11, 130.09, 128.98, 125.35, 124.63, 123.67, 122.64, 84.44, 81.93, 64.56, 37.10, 27.92
3g	7.25—7.18(m, 2H), 7.10(dt, J=7.7, 1.2 Hz, 1H), 6.81(dd, J=8.1, 2.7 Hz, 1H), 6.05(q, J=3.8 Hz, 1H), 5.93(s, 1H), 5.36(s, 3H), 3.77(s, 1H), 3.33(dd, J=11.7, 4.8 Hz, 1H), 3.00(dd, J=11.6, 2.4 Hz, 1H), 1.22(s, 9H)	160.61, 153.41, 145.32, 129.76, 120.05, 113.77, 113.24, 84.85, 80.93, 65.76, 55.48, 38.66, 28.30
3h	7.75(dd, J=7.3, 1.5 Hz, 1H), 7.22—7.04(m, 3H), 6.15(s, 1H), 6.03(s, 1H), 5.31(s, 1H), 3.36(dd, J=11.8, 4.8 Hz, 1H), 2.98(dd, J=11.8, 3.0 Hz, 1H), 2.36(s, 3H), 1.17(s, 9H)	153.43, 141.57, 135.09, 130.61, 127.92, 126.98, 126.92, 85.09, 80.82, 62.47, 38.06, 28.20, 19.28
3i	7.67(d, J=7.7 Hz, 1H), 7.35(d, J=7.9 Hz, 1H), 7.32—7.18(m, 2H), 6.24(s, 1H), 5.97(s, 1H), 4.34(s, 1H), 3.30(dd, J=12.2, 5.4 Hz, 1H), 3.07(dd, J=12.2, 5.1 Hz, 1H), 1.24(s, 9H)	153.29, 139.38, 132.00, 129.30, 128.71, 127.10, 85.14, 81.67, 61.60, 35.44, 29.69, 27.94
3j	7.68(d, J=7.7 Hz, 1H), 7.54(dd, J=8.0, 3.3 Hz, 1H), 7.41—7.27(m, 1H), 7.15(d, J=6.4 Hz, 1H), 6.20(s, 1H), 5.98(t, J=4.9 Hz, 1H), 4.35(s, 1H), 3.38—3.21(m, 1H), 3.15—3.02(m, 1H), 1.25(s, 9H)	153.32, 140.90, 132.62, 129.01, 127.77, 127.21, 122.11, 85.33, 81.71, 64.39, 35.34, 27.99
3k	7.60(d, J=8.5 Hz, 2H), 7.35(d, J=8.1 Hz, 2H), 6.08(s, 1H), 5.95(s, 1H), 5.42(d, J=4.3 Hz, 1H), 3.35(dd, J=11.7, 4.7 Hz, 1H), 3.01(dd, J=11.7, 2.1 Hz, 1H), 1.23(s, 9H)	152.31, 141.94, 132.51, 128.89, 127.96, 83.81, 80.18, 64.22, 37.98, 27.37
3l	7.48(d, J=8.2 Hz, 2H), 7.19(d, J=8.1 Hz, 2H), 6.04(s, 1H), 5.92(s, 1H), 5.27(d, J=4.4 Hz, 1H), 3.32(dd, J=11.7, 4.7 Hz, 1H), 2.99(dd, J=11.7, 2.3 Hz, 1H), 2.94—2.77(m, 1H), 1.22(d, J=6.9 Hz, 6H), 1.18(s, 9H)	152.55, 147.94, 140.04, 127.08, 125.83, 83.94, 79.93, 64.78, 37.78, 33.66, 27.38, 23.49
3m	8.16(d, J=8.4 Hz, 1H), 7.96(dd, J=8.1, 1.7 Hz, 2H), 7.85(d, J=8.2 Hz, 1H), 7.68—7.45(m, 3H), 6.84(s, 1H), 6.17(s, 1H), 5.46(s, 1H), 3.46(dd, J=11.9, 5.1 Hz, 1H), 3.08—3.00(m, 1H), 1.10(s, 9H)	152.73, 137.97, 133.78, 130.29, 128.74, 127.75, 126.07, 125.59, 125.34, 123.13, 122.92, 84.59, 80.03, 61.66, 37.27, 27.36

Scheme 3 Optimization of reaction conditions of catalysts 4a—4f

Table 3 Optimization of reaction conditionsa

Entry	Catalyst	Solvent	t/h	Yield^b(%)	d.r.^c	e.e.(%)^c
1	4a	CH₂Cl₂	2	88	1:1	20/66^d
2	4b	CH₂Cl₂	4	78	1:1	38/60
3	4c	CH₂Cl₂	2	88	2:1	33/50
4	4d	CH₂Cl₂	2	89	1:1	34/24
5	4e	CH₂Cl₂	2	97	2:1	53/34
6	4f	CH₂Cl₂	2	99	3:2	73/25
7	4f	Toluene	2	96	3:2	78/31
8	4f	CHCl₃	2	98	3:2	83/5
9	4f	1,2-Dichloroethane	2	92	3:2	74/29
10	4f	Tetrahydrofuran	2	95	3:2	69/23
11	4f	Chlorobenzene	2	96	3:2	73/34
12	4f	Acetonitrile	2	96	3:2	31/33
13	4f	Ethyl acetate	2	91	3:2	79/15
14^e	4f	CHCl₃	6	95	2:1	92/27
15^f	4f	CHCl₃	6	93	2:1	92/29
16^g	4f	CHCl₃	6	96	3:1	92/34
17^h	4f	CHCl₃	6	90	2:1	91/28
18ⁱ	4f	CHCl₃	6	85	1:1	88/43

Table 4 Substratescope of the [3+2] annulation reactiona

Entry	R	Product	Yield^b(%)	d.r.^c	e.e.(%)^d
1	Ph	3a	96	3:1	92e/34^e
2^f	4-Me-Ph	3b	95	7:1	92/34
3	3-Me-Ph	3c	93	2:1	92/37
4	3-Cl-Ph	3d	82	1:1	91/24
5	3-Br-Ph	3e	91	1:1	92/25
6	3-CF₃-Ph	3f	91	1:1	87/12
7	3-MeO-Ph	3g	95	2:1	88/29
8	2-Me-Ph	3h	88	3:2	76/26
9	2-Cl-Ph	3i	85	1:2	72/25
10	2-Br-Ph	3j	93	1:2	76/33
11	4-Cl-Ph	3k	90	2:1	95/33
12	4-i-Pr-Ph	3l	94	2:1	94/44
13	1-Naphthyl	3m	95	2:1	92/48

Scheme 4 Proposed mechanism of the [3+2] annulation reaction

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