Stereoselective Synthesis of Highly Functionalized Trisubstituted Olefins via the Aldol Reaction of Allenoxyborinates with Carbonyl Compounds
摘要:
Allenoxyborinates, generated via the reaction of dicyclohexylborane with alpha,beta-acetylenic ketones, react in situ with excess starting ketone to afford stereodefined, functionalized, trisubstituted olefins in good yields. The allenoxyborinates, (RCH=C=C(R')OB(c-C6H11)(2), can also be trapped by aldehydes and ketones when R' is a tert-butyl group.
Effects of organometals on the palladium-catalyzed tandem carbopalladation-cross coupling for preparing stereodefined exocyclic alkenes
作者:Ei-ichi Negishi、Yumiki Noda、Frédéric Lamaty、Edward J. Vawter
DOI:10.1016/s0040-4039(00)97630-5
日期:1990.1
The reaction of ω-(o-iodoaryl)- and ω-(-β-iodoalkenyl)alkynes with organometals containing Zr, Sn, Al, or B in the presence of a catalytic amount of a palladium-phosphine complex, such as Pd(PPh3)4, proceeds predominantly via initial cycliccarbopalladation followed by cross coupling, whereas the corresponding reaction of organozincs tends to be dominated by direct cross coupling.
Enantioselective Synthesis of Propargylamines through Zr-Catalyzed Addition of Mixed Alkynylzinc Reagents to Arylimines
作者:John F. Traverse、Amir H. Hoveyda、Marc L. Snapper
DOI:10.1021/ol035138b
日期:2003.9.1
[reaction: see text] Addition of mixed alkynylzinc reagents to various arylimines is catalyzed by chiral amino acid-based ligand 1 and Zr(Oi-Pr)(4).HOi-Pr to afford chiral propargylamines in up to 90% ee. Oxidative removal of the o-anisidyl group affords the free amine, which can then be acylated.
Nickel-Catalyzed Tandem Coupling of Enones, Alkynes, Alkynylzincs, and Chlorotrimethylsilane
作者:Shin-ichi Ikeda、Kouji Kondo、Yoshiro Sato
DOI:10.1246/cl.1999.1227
日期:1999.11
A nickel complex catalyzes a new tandem coupling of chlorotrimethylsilane (Me3SiCl), α,β-enones 1, alkynes 2, and di(alkynyl)zincs 7 (R′ = Bu, t-Bu, Me3Si, and Ph) to give the coupling products 3. This procedure was complementary to the reaction with alkynyltins.