Magnesium-induced cyclizations of 2-(3-iodopropyl)cycloalkanones. A cyclopentane annelation method

Abstract

A process for the stereoselective construction of a cyclopentane ring onto a preexisting cycloalkanone is developed. 2-(3-Iodopropyl)cycloalkanones, obtained by known methods from the parent cyclic ketones, were converted to

Toward the Development of a General Chiral Auxiliary. A Total Synthesis of (+)-Tetronolide via a Tandem Ketene-Trapping [4 + 2] Cycloaddition Strategy

“…Similar results for other macrocyclization methods were obtained much earlier by Yoshii and co-workers during their model studies of this macrocycle formation 17d. Among the various methods examined, there were variants of Barbier cyclizations employing Mg, Zn, and Sm, including the method of Yamamoto employing metallic Ba which is reported to permit α-selective addition to carbonyl groups especially in the presence of 18-crown-6 . The results of most experiments led to uncharacterized product mixtures.…”

Construction of Bicyclic Ring Systems via a Transannular SmI2-Mediated Ketone−Olefin Cyclization Strategy

“…Preparation of Bicyclo[3.3.0]decan-1-ol 40 . ,,,− Prepared from ( E )-cyclodec-5-one 21 (50 mg, 0.32 mmol) according to the general procedure described in Method B, to afford the product after flash chromatography on Florisil, using Et 2 O−pentane (10%) as eluent (32 mg, 62%). Characterization data are in agreement with the reported literature data.…”

Synthesis of 2,7-Cyclofarnesol and 2,7-Cyclogeranylgeraniol: Prenylogs of β-Cyclogeraniol

“…All reagents were used as purchased unless otherwise described. Prenylmethyl bromide was converted into the iodide with NaI in acetone according to a published procedure . Geranylmethyl iodide was prepared from geranylmethanol with I 2 , Ph 3 P, and imidazole (88%) .…”

“…Prenylmethyl bromide was converted into the iodide with NaI in acetone according to a published procedure. 24 Geranylmethyl iodide was prepared from geranylmethanol 25 with I2, Ph3P, and imidazole (88%). 26 Samples were prepared for combustion analysis by bulb-to-bulb distillation at 0.1 mmHg (bath temperatures 100-190 °C).…”