Diisopropyl crotylboronate preparation

Diisopropyl crotylboronates, 1. These chiral crotylboranates are prepared in 98-99% ee from diisopropyl tartrate. 

Roush, W. R. Halterman, R. L. Diisopropyl Tartrate Modified E) Crotylboronates Highly Enantioselective Propionate (li)-Enolate Equivalents J. Am. Chem. Soc. 1986, 108, 294-296. Roush, W. R Ando, K. Powers, D. B. Palkowitz, A. D. Halterman, R L. Asymmetric Synthesis Using Diisopropyl Tartrate Modified ( )- and (Z)-Crotylboronates Preparation of the Chiral Crotylboronates and Reactions with Achiral Aldehydes J. Am. Chem. Soc. 1990, 112, 6339-6348. 

Roush WR. Ando K, Powers DB, Palkowitz AD, Halterman RL. Asymmetric synthesis using diisopropyl tartrate modi-Hed (E)- and (Z)-crotylboronates preparation of the chiral crotylboronates and reactions with achiral aldehydes. J. Am. Chem.Soc. 1990 112 6339-6348. 

Allylboronate 196 is prepared from the reaction of allyl magnesium bromide with trimethylborate followed by esterification with diisopropyl tartrate (DIPT) in the presence of MgS04 (Eq. (11.13)) [116]. In analogous fashion, the (E)- and (Z)-crotylboronates 219 and 213 are prepared [139] in high isomeric purity (>98%) from ( )- and (Z)-2-butene by way of the (E)- and (Z)-crotylpotassium... 

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