A two-directional approach to enantiopure 1,4-difluoro-cyclohexenes: synthesis of difluorinated cyclitol analogues.
Enantiopure 1,4-difluoro-cyclohexenes were prepared from readily available acetonide-protected (3 S,4 S)-hexa-1,5-diene-3,4-diol. In a two-directional mode, a double cross-metathesis reaction using allyltrimethylsilane as the olefinic partner, followed by electrophilic fluorination, afforded diastereomeric acetonide-protected 3,6-difluoro-octa-1,7-diene-4,5-diols. These dienes were found to be suitable substrates for ring-closing metathesis, delivering cyclohexenes featuring fluorine atoms on the two allylic positions flanking the double bond. Upon dihydroxylation, novel difluorinated cyclitol analogues were formed.
Purser
Sophie
S
University of Oxford, Chemistry Research Laboratory, Mansfield Road, Oxford, OX1 3TA, UK.
Claridge
Timothy D W
TD
Odell
Barbara
B
Moore
Peter R
PR
Gouverneur
Véronique
V