374936-65-9Relevant academic research and scientific papers
Siloxycyclopropanes in Ugi four-component reaction: A new method for the synthesis of highly substituted pyrrolidinone derivatives
Zimmer,Ziemer,Gruner,Bruedgam,Hartl,Reissig
, p. 1649 - 1658 (2007/10/03)
Reaction of methyl trimethylsiloxycyclopropanecarboxylates 3 with amino acids, tert-butylisonitrile and methanol furnished amino diacid derivatives 2 as the result of an Ugi 5-center 4-component reaction. This one-pot reaction involves β-formyl esters such as 1 as intermediate, which are liberated in situ. Adducts 2 could be thermally cyclized to provide γ-lactams 4 in good yields. The multi component reaction was combined with this cyclization process to a fairly efficient one-pot procedure. Thus, cyclopropane derivative 3a was converted into γ-lactam 4a in good yield. Two of the γ-lactams 4 were reduced with lithium aluminum hydride to give pyrrolidine derivatives 5. Based on an X-ray analysis of the major diastereomer of compound 5d, the diastereoselectivity of the 4-component reaction is discussed.
