Asymmetric synthesis of (S)- and (R)-[2-2H1]glycine via photolysis of optically active chromium carbene complexes. A comparison of stereoselectivity between chromium ketene complexes, ketenes, and ester enolates

1992 ◽  
Vol 114 (8) ◽  
pp. 2991-2994 ◽  
Author(s):  
Louis S. Hegedus ◽  
Elena Lastra ◽  
Yukitoshi Narukawa ◽  
Daniel C. Snustad
Keyword(s):  
Asymmetric Synthesis ◽  
Optically Active ◽  
Carbene Complexes ◽  
Chromium Carbene

Synthesis of optically active .beta.-lactams by the photolytic reaction of imines with optically active chromium carbene complexes

1990 ◽  
Vol 112 (3) ◽  
pp. 1109-1117 ◽  
Author(s):  
Louis S. Hegedus ◽  
Rene Imwinkelried ◽  
Marie Alarid-Sargent ◽  
Dalimil Dvorak ◽  
Yoshitaka Satoh
Keyword(s):  
Optically Active ◽  
Beta Lactams ◽  
Carbene Complexes ◽  
Photolytic Reaction ◽  
Chromium Carbene

Synthesis of β-lactams and x -amino acids by photochemical reactions of chromium carbene complexes

1988 ◽  
Vol 326 (1592) ◽  
pp. 505-510 ◽  
Keyword(s):  
Amino Acids ◽  
Photochemical Reaction ◽  
Photochemical Reactions ◽  
Optically Active ◽  
Carbene Complexes ◽  
Efficient Process ◽  
Chromium Carbene

The photochemical reaction of chromium carbene complexes with imines has been developed into an efficient process for the synthesis of β-lactams. A new route to aminocarbene complexes, involving the reaction of Na 2 Cr(CO) 5 with amides and trimethylsilyl chloride has been developed. By using this procedure, chiral, optically active aminocarbene complexes have been prepared, and their photochemical reactions with imines developed. Chiral, optically active β-lactams have been prepared with more than 90% diastereoselectivity by this procedure. Chiral, optically active aminocarbene complexes containing pendent alcohol groups have also been prepared. Photolysis of these produces aminolactones, which can be cleaved to natural and unnatural α-amino acids.

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