Albert Padwa – Synthetic applications of 1,3-dipolar cycloaddition Chemistry

Автор: Albert Padwa
Название книги: Synthetic applications of 1,3-dipolar cycloaddition Chemistry
Формат: PDF
Жанр: Химия
Страницы: 943
Качество: Изначально компьютерное, E-book

Dipolar cycloaddition reactions have found many useful applications in chemistry, particularly with respect to the synthesis of compounds with new chiral centers. Synthetic Applications of 1,3–Dipolar Cycloaddition Chemistry Toward Heterocycles and Natural Products updates the popular 1984 edition, featuring the advances made over the past twenty years and focusing on synthetic applications.

Cycloaddition reactions figure prominently in both synthetic and mechanistic
organic chemistry. The current understanding of the underlying principles in this
area has grown from a fruitful interplay between theory and experiment. The monumental
work of Rolf Huisgen and co-workers in the early 1960s led to the general
concept of 1,3-dipolar cycloaddition. Few reactions rival this process in the number
of bonds that undergo transformation during the reaction, producing products
considerably more complex than the reactants. Over the years, this reaction has
developed into a generally useful method for five-membered heterocyclic ring
synthesis, since many 1,3-dipolar species are readily available and react with a wide
variety of dipolarophiles.
The last comprehensive survey of this area dates back to 1984, when the twovolume
set edited by Padwa, ‘‘1,3-Dipolar Cycloaddition Chemistry,’’ appeared.
Since then, substantial gains in the synthetic aspects of this chemistry have
dominated the area, including both methodology development and a body of
creative and conceptually new applications of these [3þ2]-cycloadditions in
organic synthesis. The focus of this volume centers on the utility of this
cycloaddition reaction in synthesis, and deals primarily with information that has
appeared in the literature since 1984. Consequently, only a selected number of
dipoles are reviewed, with a major emphasis on synthetic applications. Both
carbonyl ylides and nitronates, important members of the 1,3-dipole family that
were not reviewed previously, are now included. Discussion of the theoretical,
mechanistic, and kinetic aspects of the dipolar-cycloaddition reaction have been
kept to a minimum, but references to important new work in these areas are given
throughout the 12 chapters.
Beyond the ability of the 1,3-dipolar cycloaddition reaction to produce heterocycles,
its importance extends to two other areas of organic synthesis, both of which
are included in the current volume. First, the heteroatom-containing cycloadducts
may be transformed into a variety of other functionalized organic molecules,
whether cyclic or acyclic. Second, many 1,3-dipolar cycloadditions have the ability
to generate rings (and functionality derived from transformations of such rings)
containing several contiguous stereocenters in one synthetic operation. The configurations
of these new stereocenters arise from the geometry of the dipole and
dipolarophile as well as the topography (endo or exo) of the cycloaddition. An
additional stereochemical feature arises when the reactive p faces of either of the
cycloaddends are diastereotopic. Relative stereocontrol in 1,3-dipolar cycloadditions
is dealt with in some detail, and asymmetric versions of these dipolar
cycloadditions represent an entirely new aspect of the current reference work.
In recent years, numerous natural and unnatural products have been prepared by
synthetic routes that have a 1,3-dipolar cycloaddition as a crucial step in their synthesis. Consequently, this reaction has become recognized as an extremely
important transformation in the repertoire of the synthetic organic chemist.