Resolution of 1-n-propoxy-3-methyl-3-phospholene 1-oxide by diastereomeric complex formation using TADDOL derivatives and calcium salts of O,O′-dibenzoyl-(2R,3R)- or O,O′-di-p-toluoyl-(2R,3R)-tartaric acid

1-n-Propoxy-3-methyl-3-phospholene 1-oxide was prepared in optically active form by extending resolution methods applying (−)-(4R,5R)-4,5-bis(diphenylhydroxymethyl)-2,2-dimethyldioxolane (‘TADDOL’) and (−)-(2R,3R)-α,α,α′,α′-tetraphenyl-1,4-dioxaspiro[4.5]decan-2,3-dimethanol (‘spiro-TADDOL’), as well as the acidic and neutral Ca2+ salts of (−)-O,O′-dibenzoyl- and (−)-O,O′-di-p-toluoyl-(2R,3R)-tartaric acid. In one case, the diastereomeric complex could be identified by single crystal X-ray analysis. The absolute P-configuration of the enantiomers of the phospholene oxide was also determined by CD spectroscopy.

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(−)-(R)-1-Propoxy-3-methyl-3-phospholene 1-oxideC8H15O2Pee >99%[α]D25=-14.6 (c 2.2, CHCl3)Absolute configuration (R)