Cyclopalladates of phosphorus ligands have emerged as importantcatalyst precursors for C–H transformations.1 The cyclopalladationof triphenyl phosphite was first reported in 1973,2 althoughpalladacycles derived from triaryl phosphites had attracted

Cyclopalladates of phosphorus ligands have emerged as importantcatalyst precursors for C–H transformations.1 The cyclopalladationof triphenyl phosphite was first reported in 1973,2 althoughpalladacycles derived from triaryl phosphites had attracted
Cyclopalladates of phosphorus ligands have emerged as important
catalyst precursors for C–H transformations.1 The cyclopalladation
of triphenyl phosphite was first reported in 1973,2 although
palladacycles derived from triaryl phosphites had attracted little
attention3 until recently.
Palladacycles of the general type 1 have found use in a wide
range of catalytic applications.4 In particular,orthometallated
triarylphosphite complexes of the type 2 and their phosphine and
carbene adducts 3 and 4 display excellent activity in the Suzuki,5–9
Stille,7,8,10 Heck11,12 and Buchwald–Hartwig amination reactions13
and in the alkoxy- and amido-carbonylation of aryl halides.14
In all these cases,where the nature of the active catalyst has
been investigated,it has been shown that the complexes 2–4 act as
a source of Pd(0),formed in situ by various reductive processes.By
contrast,the same phosphite-based palladacycles have proved to
be robust with respect to reductive elimination in various Lewis-
School of Chemistry,University of Bristol,Cantock’s Close,Bristol,UK
BS8 1TS.E-mail:r.bedford@bristol.ac.uk
† CCDC reference numbers 727729–727731 for,10a,17 and 8 respectively..
For crystallographic data in CIF or other electronic format see DOI:
10.1039/b907333g
acid catalysed processes.Thus complexes of the types 2–4 have
been shown to give good to excellent activity in the conjugate
addition of arylboronic acids and arylsiloxanes to a range of
unsaturated substrates (Scheme 1),15 as well as the allylation of
aldehydes with allyl tributyltin (Scheme 2).16 It appears that in
these cases,the Pd(II) catalyst is stabilised by the coordination of
unsaturated substrates and that the rate of catalysis is significantly
faster than the rate of reductive decomposition.

Cyclopalladates of phosphorus ligands have emerged as importantcatalyst precursors for C–H transformations.1 The cyclopalladationof triphenyl phosphite was first reported in 1973,2 althoughpalladacycles derived from triaryl phosphites had attracted
磷配体Cyclopalladates已成为重要的催化剂的C前体- H的transformations.1的亚磷酸三苯cyclopalladation首次在1973,2报道,虽然钯从三芳基磷酸酯吸引了来自小attention3直到最近.一般型发现钯在催化特别applications.4广泛使用,orthometallated的2型及其磷化氢和卡宾加成3日和4显示在良好的活动铃木,5 - 9寂静,7,8,10 Heck11,12和triarylphosphite物布赫瓦尔德-特维希氨化reactions13和烷氧基和氨基芳halides.14羰在所有这些情况下,如果在活性催化剂的性质进行了研究,它已经表明,配合物2-4的一个来源的行为钯（0）,原位形成的各种还原过程.相比之下,同样的磷酸基钯已证实就还原消除各种刘易斯化学,布里斯托尔,Cantock的关闭,英国布里斯托尔大学BS8 1TS强劲. E-mail: r.bedford@bristol.ac.uk † CCDC reference numbers 727729–727731 for, 10a, 17 and 8 respectively.. For crystallographic data in CIF or other electronic format see DOI: 10.1039/b907333g acid catalysed processes.电子邮箱：r.bedford @ bristol.ac.uk†城市当代舞蹈团的参考号码为727729-727731,10A条,17日和8分别为在CIF或其他电子数据格式晶..看到日期：10.1039/b907333g酸催化过程 2-4的类型,因此物已显示出良好的活动,以优秀的芳基共轭酸和arylsiloxanes除了大量的不饱和基范围（计划1）,15,以及与烯丙基三丁基锡（计划醛烯丙基2）.16看来,在这种情况下,钯（II）催化剂是由不饱和基的协调稳定,而催化率明显快于还原分解率.