Direct, stereospecific generation of (Z)-disubstituted allylic alcohols
A one-pot method to prepare highly functionalized (Z)-disubstituted allylic alcohols is introduced. Hydroboration of a variety of 1-bromo-1-acetylenes with dicyclohexyl borane, reaction with t-BuLi, and transmetalation to zinc generates a (Z)-disubstituted vinylzinc reagent. In situ reaction of this reagent with aldehydes generates (Z)-disubstituted allylic alcohols in high yields (81-97%). Addition to chiral protected α- or β-oxygenated aldehydes proceeds with diastereoselectivities between 6:1 and 18:1. The anti-Felkin product is obtained in most cases. Copyright
Jeon, Sang-Jin,Fisher, Ethan L.,Carroll, Patrick J.,Walsh, Patrick J.
p. 9618 - 9619
(2007/10/03)
Reaction of [(Z)-1-bromo-1-alkenyl]dialkylboranes with N-halogeno compound in THF-DMF: A novel synthesis of 1,2-disubstituted (E)-vinyl bromides
DMF-induced reaction of [(Z)-1-bromo-1-alkenyl]dialkylboranes with an N- halogeno compound results in 1,2-migration of an alkyl group from the dialkylboryl group to the α-carbon atom without elimination of the bromine atom, followed by β-elimination to provide 1,2-disubstituted (E)-vinyl bromides stereoselectively in good yields. (C) 2000 Elsevier Science Ltd.
Hoshi, Masayuki,Shirakawa, Kazuya
p. 2595 - 2598
(2007/10/03)
Stereoselective dehalogenation of (Z)-1-halo-1-alkenyldialkylborane with tributyltin hydride: The behavior of tributyltin hydride as a hydride donor
The reaction of (Z)-1-halo-1-alkenyldialkylborane (1) with tributyltin hydride (n-Bu3SnH) at 0°C or room temperature results in reductive removal of the halogen atom to afford (E)- or (Z)-1-alkenyldialkylborane whose stereochemistry depends on the dialkylboryl group and the alkenyl group of 1.
Hoshi, Masayuki,Takahata, Kimitomo,Arase, Akira
p. 453 - 456
(2007/10/03)
More Articles about upstream products of 87393-80-4