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From Sugar Lactones to Stereodefined γ‐Alkylidenebutenolides – Synthesis of Analogs of the γ‐Alkylidenebutenolide Antibiotics Lissoclinolide and Tetrenolin
Author(s) -
Görth Felix Christian,
Umland Andreas,
Brückner Reinhard
Publication year - 1998
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/(sici)1099-0690(199806)1998:6<1055::aid-ejoc1055>3.0.co;2-m
Subject(s) - chemistry , butenolide , stereoselectivity , stereochemistry , stille reaction , total synthesis , organic chemistry , catalysis
A novel strategy for the stereoselective synthesis of E ‐ or Z ‐configured γ‐alkylidenebutenolides was applied to the preparation of the model compounds 6 / 7 ( E ) and 8 / 9 ( Z ) of the antibiotics tetrenolin ( E ) and lissoclinolide ( Z ), respectively. For introducing the α‐substituents of the target molecules the butenolide triflates ul ‐ and lk ‐ 16 were subjected to Stille couplings with trans ‐Bu 3 Sn–CHCH–CH 2 –OH or trans , trans ‐Bu 3 Sn–CHCH–CHCH–CH 2 –OH (room temp., 10 min). Acetonide cleavages and bis( tert ‐butyldimethylsilylations) set the stage for introducing the C exocyclic C γ bonds through anti ‐selective ( ds = 96:4‐99:1) eliminations of triflic acid ( ul ‐ 21 → E ‐ 23 , lk ‐ 21 → Z ‐ 23 , ul ‐ 22 → E ‐ 24 , lk ‐ 22 → Z ‐ 24 ).