- Complex-induced proximity effects. Temperature-dependent regiochemical diversity in lithiation-electrophilic substitution reactions of N-BOC-2-azabicyclo[2.1.1]hexane. 2,4- and 3,5-methanoprolines.
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[reaction: see text] Azabicycle 4 and sec-butyllithium/TMEDA afford the C(1) bridgehead alpha-lithio anion at 0 degrees C. Anion quenching with carbon dioxide, methyl chloroformate, or DMF provide the bridgehead acid 8a (N-BOC-2,4-methanoproline), ester 8b, or aldehyde 8c, respectively. By contrast, at -78 degrees C these same reagents give a mixture of regioisomeric methylene and bridgehead anions whose quenching leads to mixtures of regioisomeric methylene and bridgehead acids 6a/8a, esters 6b/8b, or aldehydes 6c/8c, respectively. The previously unknown 3,5-methanoproline was prepared as its N-BOC methyl ester 6b.
- Krow, Grant R,Herzon, Seth B,Lin, Guoliang,Qiu, Feng,Sonnet, Philip E
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- Total Synthesis of Cyclobutane Amino Acids from Atelia herbert smithii
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The syntheses of two amino acids from the seeds of the legume Atelia herbert smithii, 2,4-methanoproline and 2,4-methanoglutamic acid, are described.The synthesis of third amino acid, cis-1-amino-3-(hydroxymethyl)cyclobutanecarboxylic acid and subsequent
- Hughes, Philip,Clardy, Jon
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p. 4793 - 4797
(2007/10/02)
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