Open AccessAzanorbornadienes as Thiol-Reactive Cleavable Linkers
Author(s) -
Lucrezia De Pascalis,
Srinivas Tekkam,
M. G. Finn
Publication year - 2020
Publication title -
organic letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.94
H-Index - 239
eISSN - 1523-7060
pISSN - 1523-7052
DOI - 10.1021/acs.orglett.0c01912
Subject(s) - chemistry , thiol , cleavage (geology) , furan , conjugate , pyrrole , michael reaction , stereochemistry , oxidative cleavage , reactive intermediate , combinatorial chemistry , organic chemistry , catalysis , mathematical analysis , geotechnical engineering , mathematics , fracture (geology) , engineering
Azanorbornadienes (ZNDs), prepared from pyrroles, undergo Michael reaction with thiols followed by retro-Diels-Alder (rDA) cleavage to release the starting pyrrole and a thiomaleate. Somewhat less reactive in this regard than furan-derived oxanorbornadienes, ZNDs have an additional point of variability at the pyrrole nitrogen center. Sulfonylated ZNDs were far more stable toward rDA cleavage than acylated analogues. tert -Butoxycarbonyl examples were much less reactive with thiols, rendering the rDA step slower than the initial conjugate addition.