Homoallylic alcohols can be prepared in water by allyl-, crotyl-, 1-methylallyl-, cyclohex-2-enyl-, or cinnamyl-stannation of such carbonyl compounds as aldehydes, dialdehydes, and ketones, as well as acetals. The procedure is based on: Bu2RSnCl + R′COR″ + 12H2O → R(HO)CR′R″ + 12(Bu2SnCl)2O ↓ where R = allyl, crotyl, 1-methylallyl, cyclohex-2-enyl, or cinnamyl group, R′ = H or alkyl group, R″ ≠ R′ = alkyl group. In most cases, the reaction products are obtained rapidly in high yields (80–100%). Hydrated organometallic cations Bu2RSn+(aq) are partly involved. These results, together with those already published on 2-propynyl- and allenyl-stannation, indicate the value of this procedure.
HYDRATED SIGMA-BONDED ORGANOMETALLIC CATIONS IN ORGANIC-SYNTHESIS .1. ALLYL-STANNATION, CROTYL-STANNATION, 1-METHYLALLYL-STANNATION, CYCLOHEX-2-ENYL-STANNATION, AND CINNAMYL-STANNATION OF CARBONYL-COMPOUNDS IN WATER
FURLANI, DONATELLA;MARTON, DANIELE;TAGLIAVINI, GIUSEPPE;
1988
Abstract
Homoallylic alcohols can be prepared in water by allyl-, crotyl-, 1-methylallyl-, cyclohex-2-enyl-, or cinnamyl-stannation of such carbonyl compounds as aldehydes, dialdehydes, and ketones, as well as acetals. The procedure is based on: Bu2RSnCl + R′COR″ + 12H2O → R(HO)CR′R″ + 12(Bu2SnCl)2O ↓ where R = allyl, crotyl, 1-methylallyl, cyclohex-2-enyl, or cinnamyl group, R′ = H or alkyl group, R″ ≠ R′ = alkyl group. In most cases, the reaction products are obtained rapidly in high yields (80–100%). Hydrated organometallic cations Bu2RSn+(aq) are partly involved. These results, together with those already published on 2-propynyl- and allenyl-stannation, indicate the value of this procedure.Pubblicazioni consigliate
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