Rhodium-Catalyzed Addition-Cyclization Reactions of 5-Yn-1-ones with Arylboronic Acids

Abstract

5-Yn-1-ones react with arylboronic acids in the presence of a catalytic amount of rhodium(I) complex having a diolefin ligand to afford 2-alkylidenecyclopentanols through the regioselective addition of an arylrhodium(I) species across the carbon-carbon triple bond, followed by intramolecular nucleophilic addition of the resulting vinylrhodium(I) species to the carbonyl group.

rhodium - addition-cyclization reaction - nucleophilic addition - arylboronic acid - 5-yn-1-one

References

For reviews on Rh-catalyzed carbon-carbon bond forming reactions, see:

1a Fagnou K. Lautens M. Chem. Rev.  2003,  103:  169 

1b Hayashi T. Yamasaki K. Chem. Rev.  2003,  103:  2829 

2a Sakai M. Ueda M. Miyaura N. Angew. Chem. Int. Ed.  1998,  37:  3279 

2b Batey RA. Thadani AN. Smil DV. Org. Lett.  1999,  1:  1683 

2c Fürstner A. Krause H. Adv. Synth. Catal.  2001,  343:  343 

2d Moreau C. Hague C. Weller AS. Frost CG. Tetrahedron Lett.  2001,  42:  6957 

3a Takezawa A. Yamaguchi K. Ohmura T. Yamamoto Y. Miyaura N. Synlett  2002,  1733 

3b Matsuda T. Makino M. Murakami M. Org. Lett.  2004,  6:  1257 

4a Miura T. Shimada M. Murakami M. J. Am. Chem. Soc.  2005,  127:  1094 

4b See also: Miura T. Sasaki T. Nakazawa H. Murakami M. J. Am. Chem. Soc.  2005,  127:  1390 

For a related transformation of 5-yn-1-als by a nickel catalyst, see:

5a Ni Y. Amarasinghe KKD. Montgomery J. Org. Lett.  2002,  4:  1743 

5b Mahandru GM. Liu G. Montgomery J. J. Am. Chem. Soc.  2004,  126:  3698 ; and references cited therein

6 A report on a similar reaction appeared on the Web during the preparation of this manuscript: Shintani R. Okamoto K. Otomaru Y. Ueyama K. Hayashi T. J. Am. Chem. Soc.  2005,  127:  54 

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General Procedure for Cyclization of 5-Yn-1-ones.
To an oven-dried, N₂-purged flask was added [Rh(OH)(cod)]₂ (2.28 mg, 0.5 µmol, 0.05 equiv of Rh), arylboronic acid (1.0 mmol, 5.0 equiv), 1,4-dioxane (1 mL), and H₂O (20 µL). A solution of substrate (0.2 mmol, 1.0 equiv) in 1,4-dioxane (1.0 mL) was added to the reaction mixture at r.t. After complete consumption of substrate, H₂O was added. The aqueous layer was extracted with EtOAc three times. The combined extracts were washed with brine and dried over MgSO₄. The solvent was removed under reduced pressure and the residue was purified by preparative thin-layer chromatography (hexane-EtOAc) to give the product.

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When rhodium(I) complex generated in situ from [Rh(OH)(cod)]₂ and (R)-BINAP was used, the ee was lower (55% ee) than that of the isolated [Rh(OH)(binap)]₂.