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5‐Substituted Derivatives of the Tricyclic (+)‐Sparteine Surrogate in the Enantioselective Lithiation/Stannylation of an O ‐Alkyl Carbamate
Author(s) -
Breuning Matthias,
Hein David
Publication year - 2013
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201300987
Subject(s) - chemistry , enantioselective synthesis , sparteine , substituent , alkyl , carbamate , tricyclic , selectivity , chirality (physics) , stereochemistry , organic chemistry , catalysis , chiral symmetry breaking , physics , quantum mechanics , nambu–jona lasinio model , quark
5‐Mono‐ and 5,5‐disubstituted tricyclic bispidines, derivatives of the known (+)‐sparteine surrogate, have been synthesized in four‐to‐six steps from the natural alkaloid (–)‐cytisine and evaluated as chiral ligands in the enantioselective lithiation/stannylation of an O ‐alkyl carbamate. Structure–selectivity studies revealed that a small 5‐ endo substituent is tolerated, whereas larger 5‐ endo substituents and even small 5‐ exo substituents lead to significantly reduced levels of chirality transfer.