Ricinelaidic acid lactone

Meanwhile, Mukaiyama et al. [26] developed another similar procedure, by the use of 6-phenyl-2-pyridyl esters, for the synthesis of macrocychc lactones. This method has been used in the synthesis of f - - )-ricinelaidic acid lactone 40) [27]. Thus, as shown in Scheme 13, a mixture of 6-phenyl-2-pyridone, 2-chloro-l-methylpyridinium iodide 28), and triethylamine in dichloromethane was stirred at room temperature for 1 h. To this solution was added a dichloromethane solution of the hydroxy acid 38 and triethylamine under reflux over 6 h to give the activated ester 39 in 99% yield. A dichloromethane solution of 39 was added to a / -toluenesulfonic acid solution in dichloromethane under reflux over 11 h. Acid-induced lactonization led to the macrocycle 40 in 96% yield ... 

Fuerstner, A., Langemann, K. Total Syntheses of (+)-Ricinelaidic Acid Lactone and of (-)-Gloeosporone Based on Transition-Metal-Catalyzed C-C Bond Formations. J. Am. Chem. Soc. 1997,119, 9130-9136. 

Functionalized allyltributylstannanes can also be used in the BINOL/Ti-cata-lyzed reaction and addition of P-substituted allyl groups with heteroatoms in the side chain to aldehydes has been achieved with a high degree of enantiocon-trol [ 16]. The catalytic asymmetric allylation has been successfully applied to to -tal syntheses of the macrohdes (l )-(-i-)-ricinelaidic acid lactone and (-)-gloe-osporone [21]. 

EtAlCh, a stronger Lewis acid than Me2AlCl, with a less nucleophilic alkyl group, successfully catalyzes the ene reactions of aliphatic aldehydes with terminal alkenes. Reaction of an aliphatic aldehyde with a terminal alkene and EtAlCh in CH2CI2 for a few minutes at 0 C gives the ene adduct as a 4 1 ( ) (Z) mixture in 50-60% yield. Reaction of 9-decenoic acid with 1 equiv. of acetaldehyde and 2.2 equiv. of EtAlCh affords (69) as a 4 1 ( ) (2) mixture in 66% yield. Lactonization of the ( )-isomer provides recifeiolide. Reaction of 10-undecenoic acid with 1 equiv. of heptanal and 2.2 equiv. of EtAlCh provides a 4 1 mixture of ricinelaidic acid ( )-(70) and ricinoleic acid (Z)-(70) in 41% yield (Scheme 14).27... 

---