Three approaches toward the core of halichlorine and pinnaic acid are described. The first approach entails a racemic transannular nitrone-olefin [3+2] cycloaddition from nitrone 238. Construction of the nitrone 238 began with aldehyde 241. Another key feature in this route involved a ring-closing metathesis for the formation of a 14-membered...
Intramolecular cyclization of organometallic compounds represents
a promising tool for synthesis. The reaction involves exothermic
consumption of intramolecular double bonds via insertion
into a carbon metal sigma bond. This represents an intramolecular
example of the reaction type responsible for metal catalyzed polymerization
of olefins.
Organolithium reagents were found to cyclize...
Alkylation of propylene oxide with 2-lithiofuran gave alcohol I,
which was smoothly converted to acetylfuran II. hydrogenation of II
over rhodium on charcoal followed by Jones' oxidation afforded ketone
III. Further transformation into IV was accomplished via a Wittig
reaction followed by saponification with methanolic sodium hydroxide.
Hydroboration of the...
Part 1
The pyrolysis of cis-1-trimethylsiloxy-1-cyclopr opyl-3-cyclononene in the temperature range 285-350° is described. Instead
of siloxy-Cope rearrangement, undesired desiloxylation took place.
Part 2
Gas-phase pyrolytic rearrangement of 2-phenyl-1-trimethylsiloxy-1-vinylcyclononane was investigated in a static system
in the temperature range 213-330°. It was discovered that
three major products resulted: cis- and...
An improved procedure for the preparation of β-(3-cyclohexenyl) propionic acid from 4-vinylcyclohexene was developed. The
Friedel-Crafts cyclization of β-(3-(3-cyclohexenyl) propionyl chloride
with aluminum chloride was shown to give one bicyclic chlorine
containing ketone in 41% yield. This ketone was identified by a combination of spectral and chemical methods as a...
The object of this study is the synthesis of trans-cyclopentane-1, 2-dicarboxylic acid. Five procedures designed for the synthesis of
this trans diacid are described in the literature. The procedure
devised by Perkin in 1887, Fuson and Cole in 1938, and by Brenner
in 1961 were investigated to determine which of...