Synthesis and Reactivity of α- and β-Chloro-α-phenylselanyl Esters
摘要:
Thermal decomposition of the dichloro-adducts derived from alpha-phenylselanylesters 1, 2 and 4 has been studied. N-Chloro-succinimide treatment of esters 2 was an efficient preparative method for alpha-chloro-alpha-phenylselanylesters 10 and alpha-chloro-alpha,beta-unsaturated esters 11. Some transformations of esters 10 were achieved. alpha,beta-Dichloro-alpha-phenylselanylesters 22 were prepared from beta-chloro-alpha-phenyl selanylesters 5 or by decomposition of the dichloroselenuranes 21 derived from esters 4. (C) 2000 Elsevier Science Ltd. All rights reserved.
Pictet-Spengler condensation of N-sulfonyl-β-phenethylamines with α-chloro-α-phenylselenoesters. New synthesis of 1,2,3,4-tetrahydroisoquinoline-1-carboxylates
作者:Claudio C. Silveira、Carmem R. Bernardi、Antonio L. Braga、Teodoro S. Kaufman
DOI:10.1016/s0040-4039(99)00958-2
日期:1999.7
The reaction of N-sulfonyl-β-phenethylamines with α-chloro-α-phenylseleno acetate/propionate esters under Lewis acid promotion gives moderate to good yields of the corresponding 1,2,3,4-tetrahydroisoquinoline-1-carboxylates. Varying degrees of diastereoselection were obtained using chiral sulfonamides and/or esters. Employing this strategy, the achievement of a new total synthesis of Calycotomine is
A new approach to (±)-heritonin. The preparation of β-tetralones from allylsilanes and acid chlorides
作者:Claudio C. Silveira、Alessandra Machado、Antonio L. Braga、Eder João Lenardão
DOI:10.1016/j.tetlet.2004.03.154
日期:2004.5
A new method for the preparation of 4-alkyl-β-tetralones is described, by reaction of arylacetic acidchlorides with allylsilanes. Employing β-tetralone 5, the synthesis of (±)-heritonine and (±)-epi-heritonine, natural piscicides isolated from Heritiera littoralis, was achieved in four steps and 22% overall yield. The key step of this synthesis involved the selenocarbenium ion-mediated elaboration