Highly Diastereoselective Addition of Cinnamylzinc Derivatives to α-Chiral Carbonyl Compounds
作者:Guillaume Dunet、Peter Mayer、Paul Knochel
DOI:10.1021/ol702607t
日期:2008.1.1
Cinnamylzinc reagents react with cyclic and acyclic alpha-chiral ketones under very mild conditions (-78 degrees C, 1 h), yielding the corresponding homoallylic alcohols bearing three adjacent stereocenters with high diastereoselectivity. An extension of this reaction to enantioenriched alpha-chiral ketones is also described.
Reduction of Li2MnCl4 with magnesium metal provided activated manganese as a black suspension in THF. Treatment of organichalides such as allyl bromides, α-halo esters or aryl halides with activated manganese furnished various organomanganese reagents which reacted further with electrophiles to afford the corresponding adducts. The reaction of a ketone bearing an iodoaryl moiety with this active manganese
Highly Diastereoselective Aldol Synthesis from<i>α</i>-Iodo Ketones in Aqueous Media
作者:Ikuya Shibata、Masatsugu Kawasaki、Makoto Yasuda、Akio Baba
DOI:10.1246/cl.1999.689
日期:1999.7
Highly diastereoselective aldolsynthesis from α-iodo ketones was promoted under aqueous conditions by a distannane system, (n-Bu3Sn)2, n-Bu2SnF2 and HMPA. Aqueous solutions of acetaldehyde, formaldehyde and pivaraldehyde were applicable to give β-hydroxy ketones effectively.
A novel facile method for the traceless solid-phase synthesis of α-iodo ketones using a recyclable resin-bound selenium bromide reagent is reported. Various ketones and β-dicarbonylcompounds can be converted to the corresponding α-iodo-substituted compounds in excellent yields and purities with simple workup procedure and mild conditions.