catalytic asymmetric allylic transfer reactions of achiral aldehydes with 2-ethynyl- and 2-ethenyl-2-propenylstannane promoted by BINOL-TiIV complex with synergetic reagent are achieved for the synthesis of homoenynyl- and dienyl alcohols with high levels of enantioselectivity. The range of enantioselectivity is 84−99% ee with good chemical yields. The application of catalytic asymmetric dienylation
Chiral synthesis VIA organoboranes. 26. An efficient synthesis of isoprenyl derivatives of borane - valuable reagents for the isoprenylboration of aldehydes. A convenient route to both enantiomers of ipsenol and ipsdienol in high optical purity
作者:Herbert C. Brown、Ramnarayan S. Randad
DOI:10.1016/s0040-4020(01)85575-7
日期:1990.1
namely metallation of isoprene with potassium 2,2,5,5-tetramethylpiperidide followed by sequential treatment with B-methoxydialkylborane and boron trifluoride-etherate. These reagents are used for the convenient isoprenylation of aldehydes. Reaction of isovaleraldehyde and β, β-dimethylacrolein with B2'isoprenyldiisopinocampheylborane provides both ipsenol and ipsdienol, respectively in 65% yields and 96%
B-2′-isoprenyldiisopinocampheylborane: An efficient reagent for the chiral isoprenylation of aldehydes. A convenient route to both enantiomers of ipsenol and ipsdienol
作者:Herbert C. Brown、Ramnarayan S. Randad
DOI:10.1016/0040-4039(90)87006-l
日期:1990.1
BROWN, HERBERT C.;RANDAD, RAMNARAYAN S., TETRAHEDRON LETT., 31,(1990) N, C. 455-458