Synthesis of 1,2-divinylcyclopropanes by metal-catalyzed cyclopropanation of 1,3-dienes with cyclopropenes as vinyl carbene precursors

• Jesús González,
• Alba de la Fuente,
• María J. González,
• Laura Díez de Tejada,
• Luis A. López and
• Rubén Vicente

Beilstein J. Org. Chem. 2019, 15, 285–290, doi:10.3762/bjoc.15.25

• Abstract The synthesis of 1,2-divinylcyclopropanes by the reaction of cyclopropenes with 1,3-dienes is reported. The process relies on the ability of ZnCl2 or [Rh2(OAc)4] to generate metal–vinyl carbene intermediates from cyclopropenes, which effect cyclopropanation of 1,3-dienes. Most of the reactions

• proceeded in reasonable yields while the diastereoselectivity strongly depends on the structure of the diene. An example of an intramolecular process as well as the use of furan and 1,4-cyclohexadiene as dienes are also reported. Keywords: cyclopropanation; cyclopropenes; dienes; divinylcyclopropanes

• allows sigmatropic rearrangements leading to odd-numbered carbocyclic derivatives [8]. In this sense, seven-membered carbocycles, namely 1,4-cycloheptadienes, can be forthrightly prepared from cis- or trans-1,2-divinylcyclopropanes through a Cope rearrangement [8][9]. The potential of this type of

Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

• Sebastian Krüger and
• Tanja Gaich

Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14

• (see Scheme 9) [48] was added to ketone 45 followed by elimination to give a mixture of trans/cis-divinylcyclopropanes 47/48. Photoepimerization at the temperature required for cis-DVCPR (98 °C, trans-DVCPR occurred above 140 °C) gave bicyclic 49 in good yields. (±)-Confertin (50) and (±)-damsinic acid

• give intermediate vinyl-allenecyclopropane 249, followed by a DVCPR to furnish cycloheptadiene 250. 1,2-Shift and vinyl-carbenoid formation sequences Two major pathways to generate divinylcyclopropanes using transition metal catalysis have been developed. Uemura and coworkers [204] were the first to

• and coworkers used this chemistry with propargylic acetate 255 to achieve cyclopropanation with various dienes, for example cyclopentadiene, to generate a cis/trans-mixture of divinylcyclopropanes 256. Heating of this mixture of compounds resulted in the formation of bridged tricycle 257 in good yield