Catalytic, Enantioselective Cyclopropanation of Allylic Alcohols. Substrate Generality.

Catalytic, enantioselective cyclopropanation of a broad range of allylic alcohols and one homoallylic alcohol was carried out. The cyclopropanation reagent employed was bis(iodomethyl)zinc generated by the method of Furukawa, and the chiral promoter used (10 mol %) was the N,N-bis(methanesulfonyl) derivative of (R,R)-1,2-diaminocyclohexane. Three experimental features were found to be critical for the rapid and selective cyclopropanation: (1) use of the ethylzinc alkoxide of the allylic alcohol as the substrate by prior deprotonation of the allylic alcohols by diethylzinc, (2) the formation of the zinc complex of the promoter by prior deprotonation of the bis-sulfonamide with diethylzinc, and (3) the use of added zinc iodide generated in situ from diethylzinc and iodine.

rel-(1R,6S,7S,8R,9S)-9-methyl-8-phenyl-6-[(1s,2R)-(2-phenylcyclohexyl) oxy]-4-aza-3,5-dioxatricyclo[5.2.1.0(4,9)]decane.

The structure of the title compound, C26H31NO3, was determined by X-ray crystallography. It was found to be a unique bridged tricyclic nitroso acetal. Notable features include a chair conformation of the tetrahydro-1,2-oxazine ring and a highly pyramidalized N atom [sigma angles = 314.

(2aS,3S,6S,7S,7bR)-7-[(dimethylphenyl)-silyl]-2-oxo-6-[(1R,2S)-2- phenylcyclo-hexyloxy]-2a,3,6,7,7a,7b-hexahydro-2H-1,4,5-trioxa-4a- azacyclopenta[cd]indene-3-carboxylic acid 1-methylethyl ester.

The structure of the title compound, C31H39NO7Si, was determined and found to be a fused tricyclic nitroso acetal. Remarkable features include a twist-boat conformation of the tetrahydro-1,2-oxazine ring and a highly pyramidalized N atom [Sigma (angles) = 310.6(6) degrees].

Primary closure of gastroschisis. Facilitation with postoperative muscle paralysis.

Although most surgeons prefer primary closure of gastroschisis, staged closure is most commonly needed because of marked visceroabdominal disproportion. We have modified the usual primary fascial closure by introducing postoperative muscle paralysis through the use of a nondepolarizing neuromuscular blocking agent. The result was a higher percentage of patients amenable to primary closure.