2183-89-3

Upstream product

• 623-73-4 diazoacetic acid ethyl ester 
• 106-99-0 buta-1,3-diene 
• 19956-78-6 diphenylsulfonium 2-ethoxy-2-oxoethylide 

Downstream Products

• 77210-36-7 (+)-(1S,2R)-methyl 2-vinylcyclopropane-1-carboxylate 
• 99438-14-9 (-)-(1R,2S)-methyl 2-vinylcyclopropane-1-carboxylate 
• 25047-20-5 dictyopterene A 
• 99438-13-8 (1S,2R)-N-(2-hydroxy-1-phenylethyl)-2-vinylcyclopropane-1-carboxamide 
• 99393-26-7 (1R,2S)-N-(2-hydroxy-1-phenylethyl)-2-vinylcyclopropane-1-carboxamide 
• 85914-61-0 ethyl (E)-6-phenylthio-4-hexenoate 
• 20036-40-2 1-(2-vinyl-cyclopropyl)-ethanone 
• 144072-16-2 ethyl 2-cyclopropylcyclopropanecarboxylate 
• 144072-16-2 ethyl 2-cyclopropylcyclopropanecarboxylate 
• 33156-93-3 (R)-(-)-Ectocarpene 
• 95414-54-3 Z-ethyl 2-chloro-6-phenylsulfonyl-4-hexenoate 

Relevant academic research and scientific papers

Transition-metal-catalyzed carbenoid reactions of sulfonium ylides

Olefins undergo cyclopropanation with diphenylsulfonium (ethoxycarbonyl)methylide (=diphenyl-sulfonium 2-ethoxy-2-oxoethylide; 3a) in the presence of chiral Cu(I) or Rh(II) catalysis, trans/cis Ratios and ee's of the cyclopropanes 6 obtained with this ylide in the presence of a chiral Cu(I) catalyst 7 are identical with those obtained with ethyl diazoacetate (4). In the case of catalysis with Rh(II), the trans/cis ratios of the cyclopropanes as well as the enantioselectivity change slightly upon going from the ylide 3a to diazoacetate 4.

THE DIAZO ROUTE TO 2-VINYLCYCLOPROPYLIDENES

2-Vinylcyclopropylidene (2), 3-methyl-2-vinylcyclopropylidenes (79,80) and 2-(1-propenyl)cyclopropylidenes (95,97) were generated from the corresponding nitrosoureas in methanol at room temperature.The diazo route is initiated by the formation of 2-vinylcyclopropanediazonium ions (e.g. 43) which do not undergo 1,3-carbon shifts.No cyclopentenyl products were found in weakly basic methanol where the diazonium ions prevail.Ring opening of the diazonium ions gives pentadienyl cations and products derived therefrom.Delocalisation of the pentadienyl cations was demonstrated by the distribution of deuterium and methyl labels.In the presence of strong base, 1-diazo-2-vinylcyclopropanes (e.g. 48) arise by deprotonation of the diazonium ions.Rearrangement of 48 was excluded by independent generation of the potential product, 4-diazocyclopentene (103).Substantial quantities of 3-methoxycyclopentene (108) were obtained from 103, but not from 48.The 2-vinylcyclopropylidenes 2, 79 and 95, arising by loss of nitrogen from the corresponding diazo compounds, undergo allene formation and Skatteboel rearrangement competitively.Cis-oriented methyl groups at either C-2 (81) or C-2' (97) prevent the Skattebol rearrangement.The cyclopentenylidenes 3 and 83 yield 4-methoxycyclopentes (52,86) in excess over cyclopentadiens (4,84).In the presence of methyl vinyl ether, cycloaddition of 3 and electrophilic addition of 3-cyclopentenyl cation (51) occured in a 1:14 ratio.Stereospecific formation of 52 indicates protonation of a 'foiled carbene' (3a) to give a bishomocyclopropenyl ion (51a).Our studies confirm that the various routes to 2-vinylcyclopropylidenes converge at the carbene stage.