K. Takai et al., TRANSFORMATION OF ALDEHYDES INTO (E)-1-ALKENYLBORONIC ESTERS WITH A GEMINAL DICHROMIUM REAGENT DERIVED FROM A DICHLOROMETHYLBORONIC ESTER AND CRCL2, Synlett, (9), 1995, pp. 963
Synthetically useful (E)-1-alkenylboronic esters are prepared stereose
lectively from aldehydes with one-carbon extention by using a geminal
dichromium reagent derived from a dichloromethylboronic ester, CrCl2,
and LiI under mild conditions.