Facile Double Nucleophilic Addition of Thiols and Tetraallyltin to Latent 2-Alkynals Using in situ Hydrolysis of the Imino Functionality Promoted by Tin(IV) Chloride Pentahydrate

Abstract

In the presence of SnCl₄˙5H₂O, a mixture of thiols and tetraallyltin underwent 1,4- and 1,2-addition, respectively, with the imines derived from 3-alkynals to give (Z)-1-sulfenyl-1,5-alkadien-3-ols in good yields, where the hydrolysis of the intermediary imino species was found to be crucial.

alkynes - conjugate addition - imino compound - Lewis acid - vinyl sulfide

References

1a Okamura H. Miura M. Takei H. Tetrahedron Lett.  1979,  20:  43 

1b Takei H. Miura M. Sugimura H. Okamura H. Chem. Lett.  1979,  1447 

2a Corey EJ. Shulman I. J. Am. Chem. Soc.  1970,  92:  5522 

2b Oshima K. Shimoji K. Takahashi H. Yamamoto H. Nozaki H. J. Am. Chem. Soc.  1973,  95:  2694 

2c Bernstein PR. Tetrahedron Lett.  1979,  20:  1015 

3a Boar RB. Hawkins DW. McGhie JF. Barton DHR. J. Chem. Soc., Perkin Trans. 1  1973,  654 

3b Inayama S. Kawamura T. Ohkuma T. Tetrahedron Lett.  1978,  19:  1557 

3c Trost BM. Ornstein PL. Tetrahedron Lett.  1981,  22:  3463 

3d Wenkert E. Ferreira TW. Chem. Commun.  1982,  840 

4a Ichinose Y. Wakamatsu K. Nozaki K. Birbaum J.-L. Oshima K. Uchimoto K. Chem. Lett.  1987,  1647 

4b Kuniyasu H. Ogawa A. Sato K. Ryu I. Kambe N. Sonoda N. J. Am. Chem. Soc.  1992,  114:  5902 

4c Bäckvall J.-E. Ericsson A. J. Org. Chem.  1994,  59:  5850 

4d Ogawa A. Ikeda T. Kimura K. Hirao T. J. Am. Chem. Soc.  1999,  121:  5108 

4e Waters MS. Cowen JA. McWilliams JC. Maligres PE. Askin D. Tetrahedron Lett.  2000,  41:  141 

5a Wadsworth DH. Detty MR. J. Org. Chem.  1980,  45:  4611 

5b Bury A. Joag SDM. Stirling CJ. J. Chem. Soc., Chem. Commun.  1986,  124 

5c Kodomari M. Saitoh G. Yoshitomi S. Bull. Chem. Soc. Jpn.  1991,  64:  3485 

5d Obrecht D. Gerber F. Sprenger D. Masquelin T. Helv. Chim. Acta  1997,  80:  531 

6a Shimizu M. Morita A. Kaga T. Tetrahedron Lett.  1999,  40:  8401 

6b Shimizu M. Ogawa T. Nishi T. Tetrahedron Lett.  2001,  42:  5463 

6c Shimizu M. Nishi T. Chem. Lett.  2002,  46 

6d Hachiya I. Ogura K. Shimizu M. Org. Lett.  2002,  4:  2755 

7 Stadnichuk MD. Khramchikhin AV. Piterskaya YL. Suvorova IV. Russ. J. Gen. Chem.  1999,  69:  593 

8

A Typical Procedure for the Addition Reaction: To a suspension of SnCl₄˙5H₂O (31.2 mg, 0.06 mmol) in PhCH₃ (1.5 mL) was added a solution of N-(1-phenethyl)phenyl-propargylidenamine (46.7 mg, 0.2 mmol) in CH₂Cl₂ (1.5 mL) at -85 °C, and the mixture was stirred at -85 °C for
5 min. A solution of benzyl mercaptan (37.3 mg, 0.3 mmol) in PhCH₃ (1.5 mL) was added to the resulting mixture at
-85 °C, and the mixture was stirred at -85 °C for 10 min. A solution of tetraallyltin (28.3 mg, 0.1 mmol) in PhCH₃ (1.5 mL) was added to the resulting mixture at -85 °C and the mixture was gradually warmed to r.t. during 17 h. Sat. aq NaHCO₃ was added to the mixture which was extracted with EtOAc. The combined extracts were dried (Na₂SO₄) and concentrated in vacuo to give a crude oil. Purification on silica gel TLC (n-hexane:EtOAc = 4:1 as an eluent) gave (Z)-1-benzylthio-1-phenylhexa-1,5-dien-3-ol (47.6 mg, 84%) as a colorless oil.

9

When TiCl₄ or SnCl₄ was used as a Lewis acid, only 1,4-addition of thiol was observed.

10

The olefin geometry was determined using the NOESY experiment.