This review represents a survey of stereochemical control through sigmatropic rearrangements with emphases on their mechanistic grounds and their applicabilities (and potentials) as tools for acyclic stereocontrol. The rearrangements concerned are thermally-allowed [3, 3]- and [2, 3]- sigmatropic rearrangements.
The 1st chapter deals with an introductory aspect of the stereochemistries of the sigmatropic rearrangements in general and their synthetic potentials for achieving diastereoselective synthesis (internal asymmetric induction), chirality transfer (self-immolative asymmetric synthesis), and a combination thereof.
The 2nd chapter is concerned with stereocontrol
via [3, 3]-sigmatropic rearrangements, mainly the Claisen variants. First, the general stereochemistry of the Claisen rearrangement is discussed on mechanistic grounds. Second, a variety of highly diastereoselective Claisen modifications and their applications to natural product syntheses are described. Third, the synthetic potentialities of the 1, 3-transfer of chirality
via the Claisen rearrangement are illustrated in the contexts of recent stereocontrolled syntheses of complex natural products. Fourth, the possibility of net remote asymmetric induction
via the Claisen variant is discussed.
The 3rd chapter deals mainly with stereocontrol
via the [2, 3]-Wittig rearrangement with some emphasis on recent works in our laboratory. First, the transition-state models for the [2, 3]- Wittig variants are discussed in details. Second, a variety of highly diastereoselective [2, 3]-Wittig variants and their applications to natural product syntheses are described. both the 1, 3-and 1, 4-transfers of chirality
via the [2, 3]-Wittig rearrangement are described. Fourth, the possibility of net 1, 5-asymmetric induction
via the sequential [2, 3]-Wittig-Claisen and the [2, 3]- Wittig-[2, 3]-Wittig rearrangements are discussed.
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