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A Contribution to the Asymmetric Synthesis of 3‐Amino β‐Lactams: The Diastereoselective [2+2] Cycloaddition Reaction of Chiral Aminoketene Equivalents with Enolizable Aldehyde‐Derived Imines
Author(s) -
Palomo Claudio,
Aizpurua Jesus M.,
Legido Marta,
Mielgo Antonia,
Galarza Regina
Publication year - 1997
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.19970030909
Subject(s) - chemistry , trimethylsilyl , cycloaddition , aldehyde , lithium (medication) , alkyl , ammonia , medicinal chemistry , lactam , ammonium nitrate , organic chemistry , reaction conditions , combinatorial chemistry , catalysis , medicine , endocrinology
N ‐[Bis(trimethylsilyl)methyl]imines 9 show unique chemical properties when compared with conventional imines. Their reaction with optically pure aminoketenes derived from dehydrochlorination of 14 and 15 affords the corresponding 3‐amino‐4‐alkyl‐β‐lactams 16 and 17 in good yields and high diastereoselectivities. The mild deprotection of bis(trimethylsilyl)methyl‐ and phenyloxazolidinone moieties with, respectively, cerium(IV) ammonium nitrate and lithium/ammonia or hydrogen/Pd(OH) 2 allows the preparation of a variety of β‐lactam antibiotic building blocks.