Enhanced cis-selectivities in olefination reactions employing ylides with modified stationary groups

Whereas triphenylphosphonioethanide manifests unsatisfactory cis-selectivities (84.0-95.5%), tris(o,o'-difluorophenyl)- and tri-o-tolylphosphonioethanide react with aliph. or arom. aldehydes and, resp., 2-alkenals or 2-alkynals to afford the olefins with cis/trans-ratios of 99:1 and 96:4 (or better). Triphenylphosphoniobutanide like other higher-homolog std. ylides shows excellent stereoselectivity (99% cis) when condensed with aliph. aldehydes but fails to produce cis-olefins derived from arom. aldehydes with >96% or 97% isomeric purity. In such cases tris(o,o'-difluorophenyl)phosphoniobutanide gave a 99% level of selectivity. [on SciFinder (R)]


Published in:
Chimia, 40, 7-8, 246-7
Year:
1986
Keywords:
Note:
CAN 106:67399
29-7
Organometallic and Organometalloidal Compounds
Inst. Chim. Org.,Univ. Lausanne,Lausanne,Switz.
Journal
0009-4293
written in English.
766-90-5P; 873-66-5P; 1005-64-7P; 1560-09-4P; 3909-96-4P; 7642-04-8P; 7642-05-9P; 7642-15-1P; 7642-18-4P; 13389-42-9P; 14850-23-8P; 16002-93-0P; 20063-92-7P; 20237-46-1P; 31552-03-1P; 31552-04-2P; 60919-80-4P; 74392-44-2P; 74783-52-1P; 74783-53-2P; 106445-95-8P; 106445-96-9P; 106445-97-0P; 106445-98-1P Role: SPN (Synthetic preparation), PREP (Preparation) (prepn. of, from phosphorus ylide and aldehyde, stereochem. in); 1754-88-7; 3728-50-5; 16666-78-7; 106445-87-8; 106445-88-9; 106445-89-0; 106445-90-3; 106445-92-5 Role: RCT (Reactant), RACT (Reactant or reagent) (reaction of, with aldehydes, stereochem. in); 106445-91-4; 106445-93-6; 106445-94-7 Role: RCT (Reactant), RACT (Reactant or reagent) (reaction of, with aldehydes, stereoselectivity in); 66-25-1; 100-52-7; 100-73-2; 123-72-8; 590-86-3; 2579-22-8; 6728-26-3; 14371-10-9; 16666-79-8; 27593-24-4 Role: RCT (Reactant), RACT (Reactant or reagent) (reaction of, with phosphorus ylides, stereochem. in)
Laboratories:




 Record created 2006-03-03, last modified 2018-01-27


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