The addition of dialkylzincs or diphenylzinc to substituted phenylacetylenes in the presence of catalytic amounts of Ni(acac)(2) in THF : NMP mixtures produces syn-carbozincation products with good to excellent regio-and stereoselectivity. After quenching with an electrophile (iodine, acyl chloride, allyl bromide) tetrasubstituted olefines are obtained in good to satisfactory yields. An intramolecular version of the reaction is possible using a terminal triple bond bearing an iodine at a remote position. More substituted iodo-alkynes furnish only reductive elimination products. An application to a stereoselective synthesis of (Z)-tamoxifen (Z: E > 99: 1) has been developed. (C) 1998 Elsevier Science Ltd. All rights reserved.
Studemann; Knochel, Angewandte Chemie - International Edition in English, 1997, vol. 36, # 1-2, p. 93 - 95
作者:Studemann、Knochel
DOI:——
日期:——
Stereoselective synthesis of trisubstituted alkenylboranes by palladium-catalysed reaction of alkynyltriarylborates with aryl halides
作者:Naoki Ishida、Tomoya Miura、Masahiro Murakami
DOI:10.1039/b710472c
日期:——
The palladium-catalysed reaction of alkynyltriarylborates with aryl halides afforded trisubstituted alkenylboranes, in which two different aryl groups were installed across the carbon-carbon double bond in a cis arrangement.