Hml. Davies et al., ASYMMETRIC-SYNTHESIS OF 2,3-DIHYDROFURANS BY REACTION OF RHODIUM-STABILIZED VINYLCARBENOIDS WITH VINYL ETHERS, Journal of organic chemistry, 63(8), 1998, pp. 2641-2645
Rhodium(II) octanoate catalyzed decomposition of 2-diazo-3-siloxybuten
oates, containing (R)-pantolactone as a chiral auxiliary, in the prese
nce of vinyl ethers results in the diastereoselective synthesis of cyc
lopropanes with high asymmetric induction. Treatment of the cyclopropa
nes with tetrabutylammonium fluoride results in desilylation and ring
expansion of the resulting acylcyclopropanes to 2,3-dihydrofurans with
retention of stereochemistry.