The formation of bicyclo[n.2.0]alkan-1-ols from the reaction of the lithium enolates of simple ketones and phenyl vinyl sulfoxideElectronic supplementary information (ESI) available: full experimental details. See http://www.rsc.org/suppdata/ob/b2/b208365e/

Abstract

The enolates generated from cyclopentanone, cycloheptanone or cyclooctanone and LDA at -78 degrees C in THF react with (+/-)-phenyl vinyl sulfoxide under controlled conditions of temperature, reaction time, and concentration. Upon oxidation with MCPBA of the product mixtures, the novel sulfonylbicyclo[3.2.0]heptan-1-ols10-12,sulfonylbicyclo[5.2.0]-nonan-1-ols 16-18, and sulfonylbicyclo[6.2.0]decan-1-ols 21 and 22 in conjunction with alkylated ketones 8, 9, 15, 19 and 20 were obtained from the respective ketones. The enolate generated from cyclobutanone and LDA at -78 degrees C in THF reacts with (+/-)-phenyl vinyl sulfoxide and upon oxidation with MCPBA, the cyclohexanone 4 and monoalkylated cyclobutanone 5 were obtained. The ratio of bicyclo[n.2.0]alkan-1-ol to alkylated products varied with the ketone enolate, conversion of phenyl vinyl sulfoxide, time, temperature and concentration of reaction and the stability and steric strain of the final bicyclo[n.2.0]alkan-1-ol product.

Probing the Formation of Bicyclo[4.2.0]octan-1-ols

“…Thermodynamic Control. In previous work we had shown that, within a 24 h time course experiment, the ratio of sulfinylbicyclooctanols 1 − 3 to the monoalkylated ketone 4 decreased from 91:9 at 15 min reaction time, with the monoalkylated ketone 4 being the only product at 24 h. Likewise, increased reaction temperature promoted the formation of the monoalkylated ketone 4 …”

“…Optical rotations were measured on a Jasco P-1020 Polarimeter. Bicyclo[ n .2.0]octan-1-ols 1 − 3 , 5 ,15a 6 , 7 ,15a 8 , 9 ,15a 10 , 24 ,15a and monoalkylated ketone 4 13,46 have been characterized previously.…”

“…In a further study we demonstrated that a range of simple ketones of varying ring sizes (five- to eight-membered) can react likewise with phenyl vinyl sulfoxide. Upon oxidation with m -chloroperoxybenzoic acid (MCPBA), sulfonylbicyclo[3.2.0]heptan-1-ols 5 and 6 , sulfonylbicyclo[5.2.0]nonan-1-ols 7 and 8 , and sulfonylbicyclo[6.2.0]decan-1-ols 9 and 10 were obtained in partially optimized yields of 27.5−70% (Chart ) . In addition, structuralaspects of selected sulfonylbicyclo[ n .2.0]alkanols were reported .…”

Catalytic (2 + 2)-Cycloaddition Reactions of Silyl Enol Ethers. A Convenient and Stereoselective Method for Cyclobutane Ring Formation

“…Vinyl sulfides or selenides have been employed in similar stepwise reactions . In contrast, cyclobutane formation from silyl enol ethers, which are one of the most easily prepared ketone-equivalents, has not been achieved except in a limited number of cases. , A significant problem with some of the reported reactions is that simple α,β-unsaturated esters have reactivity lower than that of esters of alkynyl and allenyl carboxylates and other highly electron-deficient olefines 1 …”