Imine Allylations by Allylic Trichlorotins Derived from α,α-Diisopropylhomoallylic Alcohols with Tin(II) Chloride and N-Chlorosuccinimide

Abstract

Allylic trichlorotins, prepared in situ from α,α-diisopropylhomoallylic alcohols with tin(II) chloride and N-chlorosuccinimide in dichloromethane at -40 ºC, cause nucleophilic addition to N-tosylimines or N-tosyliminiums to afford the corresponding α-substituted homoallylic amines.

Key words

nucleophilic additions - allylations - organometallic reagents - allylic tins - homoallylic amines

References

• 1 For a review, see: Yamamoto Y. Asao N. Chem. Rev.  1993,  93:  2207 
• For recent non-Barbier-type imine allylations using imines, iminiums, oximes, hydrazones and so on, see:
• 2a Kise N. Yamazaki H. Mabuchi T. Shono T. Tetrahedron Lett.  1994,  35:  1561 
• 2b Hoffman RV. Nayar NK. Shankweiler JM. Klinekole BW. Tetrahedron Lett.  1994,  35:  3231 
• 2c Panek JS. Jain NF. J. Org. Chem.  1994,  59:  2674 
• 2d Basile T. Bocoum A. Savoia D. Umani-Ronchi A. J. Org. Chem.  1994,  59:  7766 
• 2e Bellucci C. Cozzi PG. Umani-Ronchi A. Tetrahedron Lett.  1995,  36:  7289 
• 2f Wang D.-K. Dai L.-X. Hou X.-L. Tetrahedron Lett.  1995,  36:  8649 
• 2g Veenstra SJ. Schmid P. Tetrahedron Lett.  1997,  38:  997 
• 2h Kobayashi S. Iwamoto S. Nagayama S. Synlett  1997,  1099 
• 2i Billet M. Klotz P. Mann A. Tetrahedron Lett.  2001,  42:  631 
• 2j Hirabayashi R. Ogawa C. Sugiura M. Kobayashi S. J. Am. Chem. Soc.  2001,  123:  9493 
• 2k Aspinall HC. Bissett JS. Greeves N. Levin D. Tetrahedron Lett.  2002,  43:  323 
• For Barbier-type imine allylations, see:
• 3a Chan TH. Lu W. Tetrahedron Lett.  1998,  39:  8605 
• 3b Lu W. Chan TH. J. Org. Chem.  2000,  65:  8589 
• 3c Vilaivan T. Winotapan C. Shinada T. Ohfune Y. Tetrahedron Lett.  2001,  42:  9073 
• 3d Wallner OA. Szabó KJ. Org. Lett.  2002,  4:  1563 
• 4a Masuyama Y. J. Synth. Org. Chem. Jpn.  1992,  50:  202 
• 4b Masuyama Y. In Advances in Metal-Organic Chemistry   Vol. 3:  Liebeskind LS. JAI Press; Greenwich: 1994.  p.255 
• 4c Masuyama Y. In Recent Research Developments in Organic Chemistry   Vol. 4:  Transworld Research Network; Trivandrum, India: 2000.  p.373 ; and references cited therein
• 7a Tagliavini G. Rev. Silicon, Germanium, Tin, Lead  1985,  8:  237 
• 7b Jones P. Knochel P. J. Org. Chem.  1999,  64:  186 ; and references cited therein
• 8 Masuyama Y. Saeki K. Horiguchi S. Kurusu Y. Synlett  2001,  1802 
• 9 Masuyama Y. Tosa J. Kurusu Y. Chem. Commun.  1999,  1075 

5

The use of imines such as N-benzylideneaniline and N-benzylidenetosylamide in the allylation with tin(II) halides did not afford homoallylic amines but homoallylic alcohols in low yields.

6

Tin(II) chloride is insoluble in dichloromethane, and dissolves in dichloromethane containing an equimolar amount of alcohol to the tin(II) by adding an equimolar amount of NCS to the tin(II).

10

The syn-diastereoselectivity in the allylations by 5 was confirmed by the comparison of ¹H NMR spectra with authentic samples prepared by the imine allylation by 1-bromo-2-butene with indium. [3] In addition the diastereo-selectivity in ref. [9] has been mistaken; syn adducts are major, similarly to the imine allylation by 5.

11

The E:Z ratio of A could not be determined by the ¹H NMR observation of the reaction of 5 with SnCl₂ and NCS in CD₂Cl₂ either at -40 ºC or at room temperature. Since the E:Z ratios of α-adducts in the carbonyl allylation by 5 are ca. 1:1 to 1:4, [8] the 2-butenyltrichlorotin intermediate is presumed to be an E,Z mixture.