Reductive Cyclisation of Azidolactams with Bu₃P/LiAlH₄

Abstract

Octahydropyrrolo[2,3-b]pyrroles were synthesised by treatment of azidolactams successively with tri-n-butylphosphine and LiAlH₄.

Key words

azides - lactams - aminals - bicyclic Compounds - heterocycles

References

• 1 Thorsett ED. Harris EE. Patchett AA. J. Org. Chem.  1978,  43:  4276 
• 2 Daoust B. Lessard J. Tetrahedron  1999,  55:  3495 
• 3 Masamune S. Kaiho T. Garvey DS. J. Am. Chem. Soc.  1982,  104:  5521 
• 4 Amine 7 was identified in the crude reaction mixture by comparison with an authentic sample, generated by reduction of 5 with Ph₃P/H₂O; see: Gololobov YG. Zhmurova IN. Kasukhin LF. Tetrahedron  1981,  37:  437 
• 5 Red-Al^® has previously been used for the reductive cyclisation of azido-oxindoles: Overman LE. Paone DV. J. Am. Chem. Soc.  2001,  123:  9465 
• 7 Coates B. Montgomery DJ. Stevenson PJ. Tetrahedron  1994,  50:  4025 
• 8 Abdel-Baky S. Giese RW. J. Org. Chem.  1986,  51:  3390 

6

Thorsett et al. (ref. [1] ) report a coupling constant of 7 Hz between the ring junction protons in a cis-fused octahydro[2,3-b]pyrrole.

9

The relative stereochemistry of this compound is assigned by analogy to reactions in ref. [7]