（-）-Tetrahydrolipstatin 1 was synthesized in three steps and 33.8% overall yield from aldehyde 6 by tandem Mukaiyama-aldol lactonization, which offered a concise, efficient and highly diastereoselective route to thi...（-）-Tetrahydrolipstatin 1 was synthesized in three steps and 33.8% overall yield from aldehyde 6 by tandem Mukaiyama-aldol lactonization, which offered a concise, efficient and highly diastereoselective route to this antiobesity drug. We also presented a resolution method for preparation of the crucial intermediate, β- （t-butyldimethylsilyloxy）tetradecanal.展开更多
Efficient Mukaiyama-type aldol reaction of 1, 2-bis(trimethylsiloxy)cyclobutene with aromatic aldehydes catalyzed by MgI2 is reported. The resulting succinoylation product of aldehyde was converted into the synthetic...Efficient Mukaiyama-type aldol reaction of 1, 2-bis(trimethylsiloxy)cyclobutene with aromatic aldehydes catalyzed by MgI2 is reported. The resulting succinoylation product of aldehyde was converted into the synthetic useful g-lactone and butenolide derivatives.展开更多
We report a general and highly efficient Mukaiyama-aldol reaction of ketones and difluoroenoxysilanes.While the reaction of aryl ketones worked efficiently in the presence of Bi(OTf)_3, that of aliphatic ketones requi...We report a general and highly efficient Mukaiyama-aldol reaction of ketones and difluoroenoxysilanes.While the reaction of aryl ketones worked efficiently in the presence of Bi(OTf)_3, that of aliphatic ketones required the use of Sc(OTf_)3. In addition, Sc(OTf)_3 was capable of achieving excellent 1,2-selectivity in the corresponding reaction of α,β-unsaturated ketones. This method provides a facile access to differently substituted β-hydroxy α,α-difluoro ketones, versatile synthons for difluomethylated tertiary alcohols.展开更多
Fluoro-1-phenyl-1-trimethylsiloxyethene reacted efficiently with aldehydes to give a-fluoro -hydroxy ke-tones in HMPA in the presence of Zn powder and CuCl.
A novel strategy was developed for a rapid access to the naturally occurring racemic neoclausenamide and its analogs, which featured a highly erythro-selective vinylogous Mukaiyama type reaction （dr= 12：1） and a hi...A novel strategy was developed for a rapid access to the naturally occurring racemic neoclausenamide and its analogs, which featured a highly erythro-selective vinylogous Mukaiyama type reaction （dr= 12：1） and a highly diastereoselective tandem conjugate addition-Davis oxidation ofN-Boc-pyrrol-2（5H）-one 5 （dr= 10：1）. Remarka- bly, the skeleton of neoclausenamide, namely 8n, an analog of neoclausenamide, was built in just two steps with all the four stereogenic centers （relative stereochemistry） established correctly and in excellent diastereoselectivities.展开更多
A practical approach to the asymmetric synthesis of the ring A substructure of genkwadane A, a daphnane diterpenoid, was developed. This synthesis features the Mukaiyama aldol reaction to introduce the quaternary ster...A practical approach to the asymmetric synthesis of the ring A substructure of genkwadane A, a daphnane diterpenoid, was developed. This synthesis features the Mukaiyama aldol reaction to introduce the quaternary stereogenic center at C4 and VO（acac）2-catalyzed Jackson-Ellman-Bolrn sulfoxidation to deliver the corresponding sulfoxide. The Dieckmann-type condensation was efficiently promoted by KHMDS and the ring A substructure was finally accomplished through Barton iodination condition.展开更多
文摘（-）-Tetrahydrolipstatin 1 was synthesized in three steps and 33.8% overall yield from aldehyde 6 by tandem Mukaiyama-aldol lactonization, which offered a concise, efficient and highly diastereoselective route to this antiobesity drug. We also presented a resolution method for preparation of the crucial intermediate, β- （t-butyldimethylsilyloxy）tetradecanal.
基金We are grateful for the financial supports from the National Outstanding Youth Fund (No. 29925204) the Foundation for University Key Teacher by the Ministry of Education of China and a Visiting Fund of the National Laboratory of Applied Organic Chem
文摘Efficient Mukaiyama-type aldol reaction of 1, 2-bis(trimethylsiloxy)cyclobutene with aromatic aldehydes catalyzed by MgI2 is reported. The resulting succinoylation product of aldehyde was converted into the synthetic useful g-lactone and butenolide derivatives.
基金supported by the National Basic Research Program of China (2015CB856600)the National Natural Science Foundation of China (21472049)
文摘We report a general and highly efficient Mukaiyama-aldol reaction of ketones and difluoroenoxysilanes.While the reaction of aryl ketones worked efficiently in the presence of Bi(OTf)_3, that of aliphatic ketones required the use of Sc(OTf_)3. In addition, Sc(OTf)_3 was capable of achieving excellent 1,2-selectivity in the corresponding reaction of α,β-unsaturated ketones. This method provides a facile access to differently substituted β-hydroxy α,α-difluoro ketones, versatile synthons for difluomethylated tertiary alcohols.
基金the National Natural Science Foundation Of China (Nos. 20272026 and D20032010).
文摘Fluoro-1-phenyl-1-trimethylsiloxyethene reacted efficiently with aldehydes to give a-fluoro -hydroxy ke-tones in HMPA in the presence of Zn powder and CuCl.
文摘A novel strategy was developed for a rapid access to the naturally occurring racemic neoclausenamide and its analogs, which featured a highly erythro-selective vinylogous Mukaiyama type reaction （dr= 12：1） and a highly diastereoselective tandem conjugate addition-Davis oxidation ofN-Boc-pyrrol-2（5H）-one 5 （dr= 10：1）. Remarka- bly, the skeleton of neoclausenamide, namely 8n, an analog of neoclausenamide, was built in just two steps with all the four stereogenic centers （relative stereochemistry） established correctly and in excellent diastereoselectivities.
文摘A practical approach to the asymmetric synthesis of the ring A substructure of genkwadane A, a daphnane diterpenoid, was developed. This synthesis features the Mukaiyama aldol reaction to introduce the quaternary stereogenic center at C4 and VO（acac）2-catalyzed Jackson-Ellman-Bolrn sulfoxidation to deliver the corresponding sulfoxide. The Dieckmann-type condensation was efficiently promoted by KHMDS and the ring A substructure was finally accomplished through Barton iodination condition.
