Ethyl 1-iodopropionate, from

Ethylidenecyclohexylamine, 50,66 Ethyl 1-iodopropionate, from ethyl 1-hydropropionate, methyl iodide, and triphenyl phosphite, 51,47 ETHYL 6-METHYLPYRIDINE-2-ACE-TATE, 52, 75... 

ETHYL 3-(p-CYAN0PHENYL)PR0PI0NATE FROM ETHYL 3-IODOPROPIONATE AND p-CYANOPHENYLZINC BROMIDE... 

A new synthesis of ( )-menthofuran (155) has been described which involves a three-step reaction sequence from the cyclohexanone (152) via direct C-alkylation with ethyl 2-iodopropionate to give (153) (Scheme 35). Hydrolysis of the diester (153) with hydrochloric acid afforded 3,6-dimethyl-2,4,5,6,7,7a-hexahydrobenzofuran-2-one (154). The final step in the sequence was the conversion of the a,/3-unsaturated y-lactone ring into the furan ring by reduction with lithium aluminum hydride and 2-propanol to afford (i)-menthofuran (155) in satisfactory yield (80JOC1517). 

DeCamp et al.t19l synthesized the lactone intermediate of the 1-hydroxyethylene isostere with high yields and stereoselectivity. As summarized in Scheme 10 (Section 10.6.2), the titanium homoenolate is prepared from ethyl 3-iodopropionate. The iodide is metalated with zinc/copper couple to give the iodozinc homoenolate species. The alkyltitanium homoenolate is then generated by transmetalation of the iodozinc precursor with one of the several chlorotitanium isopropoxide species. The resulting titanium homoenolate reacts with a N-protected a-amino aldehyde, leading to a mixture of 45-diastereomers. In the last step, the product is lactonized. 

The diethyl 2-(ethoxycarbonyl)ethylphosphonate is prepared in 35% yield from sodium diethyl phosphite and ethyl 3-iodopropionate. -- Similarly, methyl 2,3-dibromopropionate reacts with sodium diethyl phosphite with fonnation of diethyl 2-(methoxycarbonyl)ethylphosphonate in low yield (15%). ° Most likely, these reactions occur via an elimination-addition process promoted by the sodium diethyl phosphite. Treatment of ethyl 3-bromobutyrate with sodium dibutyl phosphite in toluene at VO C affords dibutyl l-methyl-2-(ethoxycarbonyl)ethylphosphonate in 62% yield, ... 

C-Alkylation of 1 with ethyl 2-iodopropionate gave 86 whose lactonization afforded 3,6,6-trimethylbenzofuran-2-one 87 (84CPB2249). While 1 with ethyl a-bromoacrylate in the presence of potassium carbonate in DMSO gave benzofuran 88. The reaction is due to a Michael addition of the carbanion obtained from 1 to the activated double bond of the acrylate ester to give an intermediate C-alkylated adduct that spontaneously cyclized to 88 (86ZOR2262) (Scheme 15). 

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