Stereoselective transformation of 1-alkeny ether (R1CH=CHOMe) into alkene (R1CH=CHR2) based on stereospecific elimination of the vicinal iodo(methoxy)alkane
Treatment of alkenyl methyl ether with ICl rapidly gave 1-chloro-2-iodo-1-methoxyalkane quantitatively. Without isolation, this dihalide was treated with Et3Al to afford anti-iodo(methoxy)alkane in good yield with high stereoselectivity. The stereochemistry of the starting alkenyl ether did not affect the stereochemical outcome of the product. The use of alkynylaluminum ((RC=C)(2)AlEt) resulted in alkynylation of the alpha-chloro-beta-iodoether. Anti-iodo(methoxy)alkane was converted into (Z)-alkene upon treatment with n-BuLi in hexane-ether at -78 degrees C. On the other hand, the reaction of the same anti-iodo(methoxy)alkane with allylsilane-TiCl4 provided (E)-alkene. (C) 1998 Elsevier Science Ltd. All rights reserved.
Hydroalumination of 3-butyn-1-ol: Application to a stereoselective synthesis of (3E,5Z)-3,5-dodecadienyl acetate, the sex pheromone of the leaf roller moth
作者:J. Michael Chong、Matthew A. Heuft
DOI:10.1016/s0040-4020(99)00899-6
日期:1999.12
Chemo-, regio-, and stereoselective hydroboration of conjugated enyne alcohol/amine: facile synthesis of Z , Z -/ Z , E -1,3-dien-1/2-ylboronic ester bearing hydroxyl/amino group
Hydroboration of conjugated enyne alcohol/amine is studied by using copper salts and bis(pinacolato)diboron as pre-catalysts and boron source respectively. It is suggested that the chemo-selectivity is derived from a combined electronic influence of the heteroatoms on the substrate and the ligand on the transition metal. The regioselectivity is probably dominated mainly by electronic effect of the
Synthesis of (3<i>E</i>, 5<i>Z</i>)-3,5-Dodecadienylacetate, the Sex Pheromone of<i>Phtheochroa cranaodes</i>(<i>Lepidoptera: Tortricidae</i>)
作者:Jhillu Singh YADAV、Etukala Jagan REDDY
DOI:10.1271/bbb.64.1726
日期:2000.1
(3E, 5Z)-3,5-Dodecadienyl acetate, the female sexpheromone of Phtheochroacranaodes, was regio and stereo-selectively synthesized from 1-octyne and (E)-4bromo-3-buten-1-ol by using Pd(PPh3)4, CuI and piperidine to afford the enyne (5). Further elaboration afforded the target pheromone. The synthetic pheromone was identified with the natural product by its MS and IR, data GLC retention time and biological