Novel synthesis of cyclic alkenylboronates via ring-closing metathesis
Novel synthesis of cyclic alkenylboronates via ring-closing metathesis
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DOI：
10.1021/ja980958i
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发表时间：
1998-08-12
影响因子：
15
通讯作者：
Ouellet, SG
中科院分区：
文献类型：
--
作者：
Renaud, J;Ouellet, SG
The versatility and synthetic applicability of the ring-closing metathesis (RCM) reaction in the construction of functionalized carbocycles and heterocycles has recently been demonstrated by a number of groups. 1, 2 The emergence of the well-defined transition metal catalysts 13 and 2a, b4, 5 has greatly expanded the scope and utility of this method. Of distinct significance is the high tolerance of the alkylidene complexes 2a and 2b to commonly encountered functional groups. Various dienes, bearing substituents in the tether linking the olefins, have been shown to undergo metal alkylidene-catalyzed cyclizations. 1 Notably however, RCM has predominantly been exploited for the preparation of cyclic entities containing unsubstituted alkene moieties. In cases where the olefin is functionalized, substituents encountered are either carbon or oxygen. 1, 6-8 We were intrigued by the possibility of employing such a strategy to access boronsubstituted cyclic olefins (eq 1). Alkenylboronic esters and acids are highly valuable synthetic intermediates, particularly with regards to carbon-carbon bond formation through palladiumcatalyzed Suzuki coupling reactions. 9 Moreover, the propensity of vinylboronates to undergo oxidation furnishes a route for the preparation of ketones. 10 In this communication, we disclose that five-, six-, and seven-membered carbocyclic and heterocyclic alkenylboronates are synthesized in high yield via metathesis of acyclic olefinic boronates.
