A series of propargylic tertiary alcohols decorated with an sp2-hybridised nitrogen donor were kinetically resolved by reagent-controlled dehydrogenative SiâO coupling with a strained, highly reactive silicon-stereogenic cyclic silane.
Synthesis of Unsymmetrically Substituted 1,3-Butadiynes and 1,3,5-Hexatriynes via Alkylidene Carbenoid Rearrangements
作者:Annabelle L. K. Shi Shun、Erin T. Chernick、Sara Eisler、Rik R. Tykwinski
DOI:10.1021/jo026481h
日期:2003.2.1
Unsymmetrically substituted 1,3-butadiynes and 1,3,5-hexatriynes are synthesized in four steps from commercially available aldehydes or carboxylic acids. The key step in this process involves a Fritsch-Buttenberg-Wiechell rearrangement, in which an alkylidene carbenoid intermediate subsequently rearranges to the desired polyyne. This rearrangement proceeds under mild conditions, and it is tolerant
Diversity-Oriented Synthesis of 3-Iodochromones and Heteroatom Analogues via ICl-Induced Cyclization
作者:Chengxiang Zhou、Anton V. Dubrovsky、Richard C. Larock
DOI:10.1021/jo0523722
日期:2006.2.1
The ICl-inducedcyclization of heteroatom-substituted alkynones provides a simple, highly efficient approach to various 3-iodochromones and analogues. This process is run under mild conditions, tolerates various functional groups, and generally provides chromones in good to excellent yields. Subsequent palladium-catalyzed transformations afford a rapid increase in molecular complexity and a convenient
Modification of the Fritsch–Buttenberg–Wiechell rearrangement: a facile route to unsymmetrical butadiynes
作者:Erin T Chernick、Sara Eisler、Rik R Tykwinski
DOI:10.1016/s0040-4039(01)01901-3
日期:2001.12
echell rearrangement has been used to form unsymmetrically substituted 1,3-butadiynes from 1,1-dibromo-olefin precursors. The reaction proceeds via lithium–halogen exchange, followed by migration of the aryl or alkynyl moiety to provide the butadiyne framework. The facile formation of the dibromo-olefins in three steps from commercially available aryl aldehydes or carboxylic acid chlorides makes this
β-Silyl-Assisted Tandem Diels–Alder/Nazarov Reaction of 1-Aryl-3-(trimethylsilyl) Ynones
作者:Rachael A. Carmichael、Punyanuch Sophanpanichkul、Wesley A. Chalifoux
DOI:10.1021/acs.orglett.7b00911
日期:2017.5.19
A one-pot tandem Diels–Alder/Nazarov reaction of 1-aryl-3-(trimethylsilyl) ynones has been achieved to generate carbo- and heterocyclic fused ring systems in good to excellent yields. The β-silyl effect is instrumental in accessing this otherwise challenging cascade annulation reaction. The tandem reaction proceeds in the presence of BCl3 to generate three new carbon–carbon bonds, a quaternary carbon