Synlett 2006(8): 1272-1274  
DOI: 10.1055/s-2006-939076
LETTER
© Georg Thieme Verlag Stuttgart · New York

Highly Diastereoselective Synthesis of N-tert-Butylsulfinylpropargylamines through Direct Addition of Alkynes to N-tert-Butanesulfinimines

Chang-Hua Dingb, Dong-Dong Chena, Zhi-Bin Luoa, Li-Xin Daia, Xue-Long Hou*a,b
a State Key Laboratory of Organometallic Chemistry, 354 Fenglin Road, Shanghai 200032, P. R. of China
b Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Road, Shanghai 200032, P. R. of China
e-Mail: xlhou@mail.sioc.ac.cn;
Further Information

Publication History

Received 30 November 2005
Publication Date:
05 May 2006 (online)

Abstract

Direct addition of a variety of alkynes to N-tert-butanesulfinyl aldimines in the presence of a suitable base provided the corresponding N-tert-butylsulfinylpropargylamines in high yields and high diastereoselectivity.

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X-ray analysis of products 3aa showed that main product has anti-configuration.

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Typical Procedure for 1,2-Addition of Alkynes to Imine in the Presence of LiHMDS. Phenylacetylene 2a (60 mg, 0.6 mmol) was added to the mixture of LiHMDS (0.6 mmol, 1 M solution in THF) and n-hexane (3.0 mL) at -78 °C. 2-Methyl-N-(pentylidene)-propan-2-sulfinamide 1c (57 mg, 0.3 mmol) was added subsequently and the resulting mixture was stirred for 30 min at the same temperature. Then the reaction mixture was warmed to r.t. and stirred till complete consumption of substrate (monitored by TLC). The reaction mixture was quenched with 5 mL of sat. NH4Cl aq solution. The aqueous layer extracted with CH2Cl2 (3 × 10 mL). The combined organic layer was dried over anhyd Na2SO4, filtered, and concentrated in vacuo. The crude product was purified by flash column chromatography on silical gel and gave propargylamine 3ca; 66 mg, 76% yield. 1H NMR (CDCl3/TMS): δ = 0.93 (t, J = 7.2 Hz, 3 H), 1.24 (s, 9 H), 1.34-1.53 (m, 4 H), 1.76-1.85 (m, 2 H), 3.43 (d, J = 6.0 Hz, 1 H), 4.25 (dd, J = 6.0, 13.5 Hz, 1 H), 7.27-7.32 (m, 3 H), 7.42-7.46 (m, 2 H). 13C NMR (75 MHz, CDCl3): δ = 13.98, 22.23, 22.50, 27.72, 36.57, 48.07, 56.06, 84.68, 89.05, 122.59, 128.16, 128.26, 131.70; IR (film): ν = 3249, 1491, 1045 cm-1; MS (EI): m/z (%) = 234 (1.07) [M - 57]+, 189 (28), 171 (12), 57 (100). Anal. Calcd for C17H25NOS: C, 70.06; H, 8.65; N, 4.81. Found: C, 69.94; H, 8.66; N: 4.54.

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A product with 96% de was obtained when optically active 1a and 2a were used as substrates.