Enantioselective hydroalkylation and natural product modification mediated by radical reactions
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Abstract
The enantioselective hydroalkylation of prochiral alkenes employing catalytic amount of chiral thiols was investigated. The transition metal-free process, using Et3B and air as radical initiator and H2O for catalyst regeneration, is an easy, cheap and eco-friendly way to perform this transformation under mild conditions. Cysteine-based peptides showed high enantioselectivity ratios for the haydroalkylation of 1,3-oxazolidin-2-one derivatives delivering the desired products in high yields. The investigation of a chiral system compatible with the linear pro-chiral alkenes is still on-going.
Additionally, we performed the modification of highy oxygenated forskolin via intermolecular carbon-centered radical addition to the vinyl moiety. Two less functionalized model substrates sharing the same polycyclic skeleton - manoyl oxide and its 13-epimer - were as well investigated. Highly regio- and reasonably stereoselective iodine atom transfer radical addition (ATRA) reactions were developed. The formation of tetracyclic ether derivative and in situ protection of the forskolin 1,3-diol moiety as a cyclic boronic ester were reported.
Furthermore, we took advantage of manoyl oxide and epi-manoyl oxide structure conformation and investigated the remote long range 1,5-hydrogen atom transfer. This concept is know as ”billiard reaction” or ”travelling radical”. Remote C-H functionalization of labdane diterpenoids via iodine atom transfer radical addition and further functionalization was reported.
Additionally, we performed the modification of highy oxygenated forskolin via intermolecular carbon-centered radical addition to the vinyl moiety. Two less functionalized model substrates sharing the same polycyclic skeleton - manoyl oxide and its 13-epimer - were as well investigated. Highly regio- and reasonably stereoselective iodine atom transfer radical addition (ATRA) reactions were developed. The formation of tetracyclic ether derivative and in situ protection of the forskolin 1,3-diol moiety as a cyclic boronic ester were reported.
Furthermore, we took advantage of manoyl oxide and epi-manoyl oxide structure conformation and investigated the remote long range 1,5-hydrogen atom transfer. This concept is know as ”billiard reaction” or ”travelling radical”. Remote C-H functionalization of labdane diterpenoids via iodine atom transfer radical addition and further functionalization was reported.
Date of Publication
2022
Year of graduation
2022
Theses Type
dissertation
Subject(s)
Language(s)
en
Author(s)
Hofstetter, Elena |
Faculty/Graduate School
Access(Rights)
open.access
Primary OA Publication
true