Silylation-desilylation of propargyl amides:: rapid synthesis of functionalised aldehydes and β-lactams

被引：18

作者：

Aronica, Laura Antonella ^{[1
]}

Valentini, Giulia ^{[1
]}

Caporusso, Anna Maria ^{[1
]}

Salvadori, Piero ^{[1
]}

机构：

[1] Univ Pisa, Dipartimento Chim & Chim Ind, I-56126 Pisa, Italy

来源：

TETRAHEDRON | 2007年 / 63卷 / 29期

关键词：

silylformylation; silylcarbocyclisation; desilylation; alpha; beta-unsaturated aldehydes; beta-lactams;

D O I：

10.1016/j.tet.2007.04.064

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

Propargyl functionalised beta-silylalkenals were easily prepared starting from suitable propargyl compounds by a silylformylation process. In particular the use of propargyl tosyl amides allowed the synthesis of alpha, beta-unsaturated aldehydes through a two-step sequence of silylformylation -desilylation reactions. TBAF was employed to induce the desilylation process that was performed under very mild experimental conditions and occurred along with an elimination step of the tosylamido moiety affording 2-methylaryl-2-alkenals with good yields and stereoselectivity. When the tosyl amides were reacted with a hydrosilane in the presence of catalytic amounts of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) alpha-silylmethylene-beta-lactams were synthesised through a silylcarbocyclisation process. A high chemoselectivity towards the b-lactam was observed when dialkyl propargyl amides were employed. The obtained b-lactams were easily transformed into the corresponding methylaryl-b-lactams by fluoride induced aryl migration -desilylation with total retention of configuration of the migrating group and complete stereoselectivity towards the more stable b-lactam (E)-isomer. (c) 2007 Published by Elsevier Ltd.

引用

页码：6843 / 6854

页数：12

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