Synthesis of highly oxygenated enantiomerically pure cis-bicyclo[4.3.0]nonanes from secondary sugar allyltin derivatives
摘要:
Secondary sugar allyltin derivatives of the D-series: Sug-CH(SnBu3)-CH=CH2 (obtained in an S(N)2' reaction of the corresponding primary allylic mesylates with 'Bu3SnCu') with the S-configuration at the stereogenic center bearing the -SnBu3 group decompose at 140degreesC to dienoaldehydes: CH2=CH-CH=CH-[(CHOR)(3)]-CHO with the cis geometry across the internal double bond. Such aldehydes react with the stabilized Wittig reagents to afford trienes, cyclization of which provides highly oxygenated enantiomerically pure cis-bicyclo[4.3.0]nonenes. This methodology is complementary to that recently proposed by us leading to such bicyclic systems, but with the trans junction between the five- and six-membered rings. (C) 2003 Elsevier Science Ltd. All rights reserved.
Stability of regioisomeric sugar allyltins. Cleavage of the carbon oxygen bond under radical conditions
摘要:
Secondary sugar allyltin derivatives [Sug-CH(SnBu3)-CH=CH2] decompose at high temperature (140 degreesC) with elimination of the tin moiety and opening of the sugar ring. The cis-dienoaldehydes thus formed react with Ph3P=CH-CO2Me to afford the corresponding trienes, which spontaneously undergo stereoselective intramolecular [4+2] cycloaddition to optically pure, highly oxygenated bicyclo[4.3.0]nonene derivatives. Primary sugar allyltins [Sug-CH=CHCH2-SnBu3] are thermally stable and do not decompose up to 170 degreesC. (C) 2001 Elsevier Science Ltd. All rights reserved.
Stability of regioisomeric sugar allyltins. Cleavage of the carbon oxygen bond under radical conditions
作者:Sławomir Jarosz、Katarzyna Szewczyk
DOI:10.1016/s0040-4039(01)00239-8
日期:2001.4
Secondary sugar allyltin derivatives [Sug-CH(SnBu3)-CH=CH2] decompose at high temperature (140 degreesC) with elimination of the tin moiety and opening of the sugar ring. The cis-dienoaldehydes thus formed react with Ph3P=CH-CO2Me to afford the corresponding trienes, which spontaneously undergo stereoselective intramolecular [4+2] cycloaddition to optically pure, highly oxygenated bicyclo[4.3.0]nonene derivatives. Primary sugar allyltins [Sug-CH=CHCH2-SnBu3] are thermally stable and do not decompose up to 170 degreesC. (C) 2001 Elsevier Science Ltd. All rights reserved.
Synthesis of highly oxygenated enantiomerically pure cis-bicyclo[4.3.0]nonanes from secondary sugar allyltin derivatives
Secondary sugar allyltin derivatives of the D-series: Sug-CH(SnBu3)-CH=CH2 (obtained in an S(N)2' reaction of the corresponding primary allylic mesylates with 'Bu3SnCu') with the S-configuration at the stereogenic center bearing the -SnBu3 group decompose at 140degreesC to dienoaldehydes: CH2=CH-CH=CH-[(CHOR)(3)]-CHO with the cis geometry across the internal double bond. Such aldehydes react with the stabilized Wittig reagents to afford trienes, cyclization of which provides highly oxygenated enantiomerically pure cis-bicyclo[4.3.0]nonenes. This methodology is complementary to that recently proposed by us leading to such bicyclic systems, but with the trans junction between the five- and six-membered rings. (C) 2003 Elsevier Science Ltd. All rights reserved.