Pb(OAc)4 mediated transannular oxidative ring cleavage

Pb(OAc)4 oxidation of homoallylic alcohols at room temperature leads to the formation of a variety of fragmentation products, whose formation requires spatial proximity of the alcohol and the olefin moieties.

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1-Allyl-5,6-bis(tert-butyldimethylsilyloxy)-7a-methyl-2,3,5,6,7,7a-hexahydro-1H-inden-1-olC25H48O3Si2Ee = 97%[α]D20=-96 (c 1.5, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1R,5S,6R,7aS)

1-Allyl-7a-methyl-2,3,5,6,7,7a-hexahydro-1H-indene-1,5,6-triolC13H20O3Ee = 97%[α]D20=-78 (c 1.2, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1R,5S,6R,7aS)

Acetic acid-9-acetoxy-7-methyl-6-oxo-2,10-dioxa-tricyclo[5.3.1.03,8]undec-3-yl esterC14H18O7Ee = 97%[α]D20=+17 (c 1.3, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1R,3R,7S,8S,9S)

5-tert-Butoxy-7-hydroxy-4,7-dimethylbicyclo[2.2.2]octan-2-oneC14H24O3Ee = 97%[α]D20=+52 (c 0.6, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,4R,5S,7S)

5-tert-Butoxy-4,7-dimethyl-2-methylenebicyclo[2.2.2]octan-7-olC15H26O2Ee = 97%[α]D20=+72 (c 1.0, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1R,4S,5S,7S)

(5-tert-Butoxy-4-methyl-2-methylenebicyclo[2.2.2]octan-7-yloxy)(tert-butyl)dimethylsilaneC20H38O2SiEe = 97%[α]D20=+49 (c 0.6, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,4R,5S,7S)

5-tert-Butoxy-4-methyl-7-methylenebicyclo[2.2.2]octan-2-olC14H24O2Ee = 97%[α]D20=+48 (c 0.9, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,2S,4R,5S)

7-Allyl-5-tert-butoxy-7-hydroxy-4-methylbicyclo[2.2.2]octan-2-oneC16H26O3Ee = 97%[α]D20=+66 (c 1.0, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,4R,5S,7S)

7-Allyl-5-tert-butoxy-4-methyl-2-methylenebicyclo[2.2.2]octan-7-olC17H28O2Ee = 97%[α]D20=+79 (c 1.0, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1R,4S,5S,7S)

2-tert-Butoxy-5-(tert-butyldimethylsilyloxy)-1-methyl-8-methylenebicyclo[2.2.2]octan-7-yl ethanoateC22H40O4SiEe = 97%[α]D20=+83 (c 1.5, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1R,2S,4S,5S,7R)

2-tert-Butoxy-5-(tert-butyldimethylsilyloxy)-1-methyl-8-methylenebicyclo[2.2.2]octan-7-olC20H38O5SiEe = 97%[α]D20=-16 (c 1.3, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,2S,4S,5S,7R)

(5-tert-Butoxy-3-(methoxymethoxy)-4-methyl-2-methylenebicyclo[2.2.2]octan-7-yloxy)(tert-butyl)dimethylsilaneC22H42O4SiEe = 97%[α]D20=+23 (c 1.6, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,3R,4R,5S,7S)

5-tert-Butoxy-8-(methoxymethoxy)-4-methyl-7-methylenebicyclo[2.2.2]octan-2-olC16H28O4Ee = 97%[α]D20=+11 (c 0.9, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,2S,4R,5S,8R)

2-tert-Butoxy-5-(tert-butyldimethylsilyloxy)-1-methyl-8-methylenebicyclo[2.2.2]octan-7-oneC20H36O5SiEe = 97%[α]D20=-12 (c 0.8, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1R,2S,4S,5S)

2-tert-Butoxy-5-hydroxy-1-methyl-8-methylenebicyclo[2.2.2]octan-7-oneC14H22O5Ee = 97%[α]D20=+5 (c 0.5, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1R,2S,4S,5S)

5-tert-Butoxy-4-methyl-7-methylenebicyclo[2.2.2]octane-2,8-diolC14H24O5Ee = 97%[α]D20=+10 (c 0.7, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,2S,4S,5S,8R)

4-tert-Butoxy-5-methyl-5-(2-oxopropyl)cyclohex-1-enyl)methyl ethanoateC17H28O4Ee = 97%[α]D20=+46 (c 1.6, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (4S,5S)

(1-2-tert-Butoxy-4-hydroxy-1-methyl-5-methylenecyclohexyl)propan-2-oneC15H26O5Ee = 97%[α]D20=-7 (c 0.9, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,2S,4S)

(4-tert-Butoxy-5-methyl-5-(2-oxoethyl)cyclohex-1-enyl)methyl ethanoateC16H26O4Ee = 97%[α]D20=+55 (c 1.3, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (4S,5R)

(4-tert-Butoxy-5-methyl-5-(2-oxopropyl)cyclohex-1-enyl)methyl ethanoateC17H28O4Ee = 97%[α]D20=+38 (c 1.1, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (4S,5R)

5-tert-Butoxy-4-methyl-2-methylene-4-(2-oxoethyl)cyclohexyl ethanoateC16H26O4Ee = 97%[α]D20=+30 (c 1.5, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,4R,5S)

5-tert-Butoxy-4-methyl-2-methylene-4-(2-oxopropyl)cyclohexyl ethanoateC17H28O4Ee = 97%[α]D20=+82 (c 0.7, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,4R,5S)

2-(-2-tert-Butoxy-4-hydroxy-1-methyl-5-methylenecyclohexyl)ethanalC14H24O3Ee = 97%[α]D20=+46 (c 1.8, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1R,2S,4S)

(4-tert-Butoxy-5-methyl-5-((E)-2-oxopent-3-enyl)cyclohex-1-enyl)methyl ethanoateC19H30O4Ee = 97%[α]D20=+46 (c 0.3, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (4S,5S)

5-tert-Butoxy-4-methyl-2-methylene-4-((E)-2-oxopent-3-enyl)cyclohexyl ethanoateC17H28O3Ee = 97%[α]D20=+19 (c 0.4, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,4S,5S)

(4-tert-Butoxy-6-(methoxymethoxy)-5-methyl-5-(2-oxoethyl)cyclohex-1-enyl)methyl ethanoateC18H30O6Ee = 97%[α]D20=+55 (c 1.3, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (4S,5R,6S)

(4-tert-Butoxy-5-methyl-6-oxo-5-(2-oxoethyl)cyclohex-1-enyl)methyl ethanoateC16H24O5Ee = 97%[α]D20=+15 (c 1.1, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (4S,5R)

4-tert-Butoxy-3-methyl-7-methylene-9,10-dioxa-tricyclo[4.3.1.03,8]decaneC14H22O3Ee = 97%[α]D20=-27 (c 0.5, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,3S,4S,6R,8R)

4-tert-Butoxy-3a-methyl-7-methylene-2-oxooctahydrobenzofuran-6-yl ethanoateC16H24O5Ee = 97%[α]D20=-32 (c 0.5, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (3aR,4S,6S,7aS)

(4-tert-Butoxy-3a-methyl-2-oxo-2,3,3a,4,5,7a-hexahydrobenzofuran-7-yl)methyl ethanoateC16H24O5Ee = 97%[α]D20=-40 (c 1.2, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (3aR,4S,7aS)

(5-tert-Butoxy-4-methyl-2-methylenebicyclo[2.2.2]octan-7-yloxy)(tert-butyl)dimethylsilaneC20H38O2SiEe = 97%[α]D20=+12 (c 1.2, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,4R,5S,7R)

5-tert-Butoxy-4-methyl-7-methylenebicyclo[2.2.2]octan-2-olC14H24O2Ee = 97%[α]D20=+42 (c 1.1, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (1S,2R,4R,5S)

 C15H20O6Ee = 70%[α]D20=-30 (c 0.7, CHCl3)Source of chirality: (S)-(−)-prolineAbsolute configuration: (2S,3S,4R,5S,8R,9S)