Styryl cyclopropyl

Styryl cyclopropyl ketone (42 g, 0.245 mol) was added to a solution of 26 mL aqueous hydrazine (0.42 mol) in 70 mL 95% ethanol. The mixture became warm and acquired a green color. It was allowed to stand for 45 min, and then was warmed on the steam bath for 1 h, after which excess hydrazine and solvent were removed under reduced pressure. Distillation of the residue at 164°C (1 nrniHg) gave 37.8 g 3-cyclopropyl-5-phenyl-2-pyrazoline as a light green liquid, in a yield of 86%. To a 100-mL round-bottomed flask equipped for distillation and immersed in a metal bath, was added 7.2 g KOH and 3.2 g platinized asbestos. When the bath was heated to 220°C, 37.8 g 3-cyclopropyl-5-phenyl-2-pyrazoline was added slowly. After the rapid evolution of nitrogen ceased, the product was distilled Irom the reaction mixture at 92-96°C (0.8 mmHg), and 22.5 g 2-phenylbicyclopropyl was obtained, in a yield of 74%. 

CICeH4,4-FCeH4, 2-thienyl, 3-styryl, cyclopropyl, 1-adamantyl (reaction time 3 h when R = cyclopropyl, and 21 h when R = 1-adamantyl)... 

Other transmetalations, between lithium and particularly tin derivatives, have also been examined in detail and have been utilized for synthesis of, e.g., vinyl-,53 propenyl-,54 allyl-,55 styryl-,56 cyclopropyl-,57 and benzyl-lithium.58... 

OSiMej) under the usual condition results in the silyloxycyclopropane (61). However, by performing the cyclopropanation in the presence of acetyl chloride (60 R = OSiMej, R = H) is converted directly into the cyclopropyl ester (62). " The styryl ether (63) does not react under the conditions of the Conia modification but, by employing diethylzinc, cyclopropanation is readily effected. To bring about cyclopropanation of the vinyl ether (60 R = OMe or OEt, R = H) without the formation of significant amounts of 2-alkoxymethylenecyclohexane carefully controlled conditions are necessary. " The use of diethylzinc also has the beneficial effect of increasing the product yiel in the reaction between benzobarrelene and di-iodomethane. Although all of the possible products are produced, the anti-tricyclic system (64) is by far the major product (30%). 

Pietruszka has reported the synthesis of styryl and cyclopropyl boronic esters with an acrylate functionality by applying a cross-metathesis reacTion (%]. Thus, the reaction of cyclopropyl boronate 122 with methyl acrylate gave the E-enoate 123 in 52% yield (Scheme 3.63). 

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