title: Synthesis and structure of large difluoromethylene containing alicycles by ring closing metathesis (RCM).
abstract: Cyclotetra- and cyclohexa-decane ring systems were prepared with CF2 groups spaced 1,4- and 1,6- for tetradecanes together with 1,5- and 1,6- for hexadecanes. These alicyclic systems were assembled by ring closing metathesis reactions of long terminal diolefins. Ring cyclisation by RCM was promoted by the introduction of the dithiane motif, using a sulfur compatible metathesis catalyst. This gave rise to macrocyclic E-cycloalkanes, which were hydrogenated also using a sulfur compatible catalyst. Finally the dithianes emerged as appropriate precursor motifs for the introduction of difluoromethylene groups. X-Ray structures revealed that the resultant rings have the CF2 groups located only at corner positions and that these groups dictated the overall macrocyclic ring conformations.
authors.affiliation: EaStCHEM School of Chemistry and Biomedical Sciences Research Centre, University of St Andrews, North Haugh, St Andrews KY16 9ST, UK. do1@st-andrews.ac.uk snolan@st-andrews.ac.uk.
authors.forename: Maciej
authors.initials: M
authors.lastname: Skibiński
authors.forename: César A
authors.initials: CA
authors.lastname: Urbina-Blanco
authors.forename: Alexandra M Z
authors.initials: AM
authors.lastname: Slawin
authors.forename: Steven P
authors.initials: SP
authors.lastname: Nolan
authors.forename: David
authors.initials: D
authors.lastname: O'Hagan
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D018360:Crystallography, X-Ray; D003500:Cyclization; D006845:Hydrocarbons, Fluorinated / Q000138:chemical synthesis* / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D011807:Quinolizines / Q000737:chemistry*; D013457:Sulfur Compounds / Q000737:chemistry*
chemical_list: D000475:Alkenes; D006845:Hydrocarbons, Fluorinated; D011807:Quinolizines; D013457:Sulfur Compounds; C438055:dithiane