Facile chelation-controlled reductive opening of methoxybenzylidene acetals with Bu3SnH and MgBr2. Regioselective protection strategy as MPM ethers
摘要:
A mild and efficient regioselective reductive opening of methoxybenzylidene acetals using a combination of Bu3SnH and MgBr2. OEt2, mainly via five-membered chelation intermediates is described. This reaction was applied to synthetic intermediates of myriaporon and tedanolide. (C) 2000 Elsevier Science Ltd. All rights reserved.
Thermal generation of acylketenes in diol-containing substrates results in dual macrocyclization/pyran-hemiketal formation. This transformation expands the scope of acylketene macrolactonizations and their application to the synthesis of complex macrolides. Triol and even tetrol substrates also have been closed in highly regioselective fashion. Additionally, the challenging macrolactonization of a tertiary alcohol was achieved.
A mild and efficient regioselective reductive opening of methoxybenzylidene acetals using a combination of Bu3SnH and MgBr2. OEt2, mainly via five-membered chelation intermediates is described. This reaction was applied to synthetic intermediates of myriaporon and tedanolide. (C) 2000 Elsevier Science Ltd. All rights reserved.
Dual Macrolactonization/Pyran-Hemiketal Formation via Acylketenes: Applications to the Synthesis of (−)-Callipeltoside A and a Lyngbyaloside B Model System
作者:Thomas R. Hoye、Michael E. Danielson、Aaron E. May、Hongyu Zhao
DOI:10.1002/anie.200804049
日期:2008.12.1
Thermal generation of acylketenes in diol-containing substrates results in dual macrocyclization/pyran-hemiketal formation. This transformation expands the scope of acylketene macrolactonizations and their application to the synthesis of complex macrolides. Triol and even tetrol substrates also have been closed in highly regioselective fashion. Additionally, the challenging macrolactonization of a tertiary alcohol was achieved.