The thermolysis of trans-1 -trimethylsiloxy- 1-vinylcyclotridec-
3-ene (VI-OTMS) led to the formation of two major products: 4-vinylcyclotridecanone
(VII) and cyclopentadec-5-en-l-one (VIII) after
hydrolysis. Ketone VII is produced by a concerted [3, 3] sigmatropic
shift, while ketone VIII is formed by a [1, 3] sigmatropic shift with
a concerted or diradical...
The potassium salts of a series of 1-vinylcycloalk-3-en-l-ols were found to undergo ring expanding [1, 3]-sigmatropic shifts at 25° when dissolved in hexamethylphosphoramide (HMPA) or 1, 2-dimethoxyethane (DME) with 18-crown-6. The yields and reaction rates were compared with those of the corresponding Siloxy-Cope ring expansions. These anionic cases showed about...
The thermal and anionic rearrangements of substituted 1-vinyltrans-
cyclotridec-3-en-l-ol compounds have been studied to determine
what effects substituents would have on the sigmatropic shift when
placed on the two positions of the 1-vinyl group.
For the thermal rearrangements, the a-substituted vinyl-trans-cyclotridecenols
gave both the [3,3] and [1,3] shift products of...
The potassium salts of certain 1-vinylcycloalk-3-en-l-ols have
been found to undergo sigmatropic ring expansion rearrangements in
HMPA. Preliminary investigations of several benzo-substituted medium
ring systems were undertaken in order to determine which of these
was best suited for further study. A synthetic sequence leading to
the formation of 5-methy1-6-viny1-7,8,9,10-tetrahydro-6-benzocyclo-octenol,
which...
The (±) 8,9:13,14-diseco-norestradiol, a large ring hormone
analog, and its related derivatives, were prepared by a ring expansion
approach. The key step of this approach is the establishment of the
benzocyclododecenone system via the Caubere reaction. This step
not only provides a favorable ring size, it also sets the necessary...
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...