Talk:Todd:Catalytic, Asymmetric Pictet-Spengler Reaction

Use this page for discussion. Preface questions/comments with initials.

MHT - Jan19 - the page is quite long. We could consider splitting into sections if anyone is having a browser problem, but otherwise we keep as-is. Much more convenient having everything on one page.

Things that need doing (updated 20/01/12):

Check suitability of "items arising" from the 2004 Terada and Akiyama papers Items arising from Akiyama and Terada papers: More on early work: Akiyama (2004) says these earlier reports "claim" the use of chiral B acids:

B. L. Hodous, G. C. Fu, J. Am. Chem. Soc. 2002, 124, 10006 - Reaction of pyrroles with ketenes catalysed by a PPY planar-chiral 4-(pyrrolidino)pyridine (PPY), which is Fe π-bonded complex (KAB: not sure where "Possible Intervention comes in).

C. Palomo, M. Oiarbide, J. M. Garcia, A. Gonzalez, A. Lecumberri, A. Linden, J. Am. Chem. Soc. 2002, 124, 10288 N. T. McDougal, S. E. Schaus, J. Am. Chem. Soc. 2003, 125, 12094 Y. Huang, A. K. Unni, A. N. Thadani, V. H. Rawal, Nature 2003, 424, 146.

Akiyama (2004) also mentions these "metal salt" versions: J. Inanaga, Y. Sugimoto, T. Hanamoto, New J. Chem. 1995, 19, 707 H. Furuno, T. Hanamoto, Y. Sugimoto, J. Inanaga, Org. Lett. 2000, 2, 49

Previous Bronsted acid example from Terada 6) Schreiner, P. R. Chem. Soc. ReV. 2003, 32, 289. (7) (a) Huang, Y.; Unni, A. K.; Thadani, A. N.; Rawal, V. H. Nature 2003, 424, 146. (b) McDougal, N. T.; Schaus, S. E. J. Am. Chem. Soc. 2003, 125, 12094. (8) Some other chiral charged Brønsted acid catalysts were reported, see: Nugent, B. M.; Yoder, R. A.; Johnston, J. N. J. Am. Chem. Soc. 2004, 126, 3418.

Jacobsen Strecker and Mannich history, from Terada (a) Sigman, M. S.; Jacobsen, E. N. J. Am. Chem. Soc. 1998, 120, 4901. (b) Vachal, P.; Jacobsen, E. N. Org. Lett. 2000, 2, 867. (c) Sigman, M. S.; Vachal, P.; Jacobsen, E. N. Angew. Chem., Int. Ed. 2000, 39, 1279. (d) Su, J. T.; Vachal, P.; Jacobsen, E. N. AdV. Synth. Catal. 2001, 343, 197. (e) Vachal, P.; Jacobsen, E. N. J. Am. Chem. Soc. 2002, 124, 10013. (f) Wenzel, A. G.; Lalonde, M. P.; Jacobsen, E. N. Synlett 2003, 1919. (10) Wenzel, A. G.; Jacobsen, E. N. J. Am. Chem. Soc. 2002, 124, 12964. (11) See also: (a) Okino, T.; Hoashi, Y.; Takemoto, Y. J. Am. Chem. Soc. 2003, 125, 12672. (b) Okino, T.; Nakamura, S.; Furukawa, T.; Takemoto, Y. Org. Lett. 2004, 6, 625.

Copper complex example from Terada: Marigo, M.; Kjærsgaard, A.; Juhl, K.; Gathergood, N.; Jørgensen, K. A. Chem.- Eur. J. 2003, 9, 2359.

(end of items arising)

Papers to Summarise/Check for Suitability

Enantioselective/Lewis Acids:

• Hino, T.; Nakagawa, M. Heterocycles 1998, 49, 499-531.
• Leighton Angew 2009

Enantioselective/Bronsted Acids:

The strengths of these chiral phosphoric acids is governed by: Akiyama Chem Rev 2007 Terada ChemComm 2008 Reviews: a) S.J. Connon, Angew. Chem. Int. Ed. 2006, 45, 3909–3912 b) T. Akiyama, J. Itoh, K. Fuchibe, Adv. Synth. Catal. 2006, 348, 999 – 1010 c) M. S. Taylor, E. N. Jacobsen, Angew. Chem. Int. Ed. 2006, 45, 1520–1543 d) Connon, S. J. Org. Biomol. Chem. 2007, 5, 3407–3417 e) Terada Synthesis 2010, 1929-1982 f) List, Top. Curr. Chem. 2010, 291, 395-456 g) Rueping Angewandte 2011, 50, 6706-6720

Enantioselective/Organocatalysts:

Jacobsen 2007 JACS, 129, 13404

Archived/inactive discussions:

1. KAB attempt to understand 2000 Koomen OrgLett (archived since this paper no longer included)

The figure for Table 1 gives diasteromeric ratios. Where are the diastereomers? I only the possibility for enantiomers in the product. Where's the other stereogenic centre?

They also mentioned "hydrolysis of the starting material" numerous times. I'm assuming they mean hydrolysis of the N-S bond (there doesn't seem any other reasonable place for hydrolysis of the SM to occur), but I just wanted to check.