Enantioselective iridium-catalyzed carbonyl isoprenylation <i>via</i> alcohol-mediated hydrogen transfer
作者:Ming Xiang、Guoshun Luo、Yuankai Wang、Michael J. Krische
DOI:10.1039/c8cc09706b
日期:——
Highly enantioselective iridium catalyzed carbonyl (2-vinyl)allylation or "isoprenylation" is achieved via hydrogen auto-transfer or 2-propanol-mediated reductive coupling from primary alcohol or aldehyde reactants, respectively. Using this method, asymmetric total syntheses of the terpenoid natural products (+)-ipsenol and (+)-ipsdienol were achieved.
Synthesis of optically active forms of ipsdienol and ipsenol
作者:K. Mori、T. Takigawa、T. Matsuo
DOI:10.1016/s0040-4020(01)93705-6
日期:1979.1
(R)-(-)-Ipsdienol 1″ and its antipode 1' were synthesized from (R)-(+)-glyceraldehyde acetonide and (R)-(+)-malic acid, respectively. This established the S-configuration of the naturally occurring (+)-ipsdienol. A new synthesis of (R)-(+)-ipsenol 2″ and its antipode 2' was also described. Chiral epoxides were shown to be useful intermediates for the synthesis of these chiral alcohols.
The BINOL‐derived chiral phosphoric acid (R)‐TRIP is utilized as an organocatalyst in the asymmetric isoprenylboration reaction of aldehydes, wherein hydrogen‐bond interactions play a key role in the control of enantioselectivity. A wide arrays of enantioenriched dienyl homoallyl alcohols, including two natural products (−)‐Ipsdienol and (−)‐Ipsenol, have been successfully constituted. The synthetic
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%
An improved process for preparing either optically pure enantiomer of the bark beetle pheromones ipsenol and ipsdienol is provided. The process is also applicable to the condensation of aldehydes of widely varying properties to the corresponding chiral alcohol.