Applications of the Wittig–Still Rearrangement in Organic Synthesis

Abstract

This Review traces the discovery of the Wittig-Still rearrangement and its applications in organic synthesis. Its relationship to Wittig rearrangements is discussed along with detailed analysis of E/Z- and diastereoselectivity. Modifications of the products arising from the Wittig-Still rearrangement are reviewed in the context of increased complexity in intermediates potentially useful in target-oriented synthesis. Early applications of the Wittig-Still rearrangement to modifications of steroids are reviewed as are applications to various terpene and alkaloid natural product targets and miscellaneous compounds. To the best of our knowledge, the literature is covered through December 2016.

1,5‐Allyl Shift by a Sequential Achmatowicz/Oxonia‐Cope/Retro‐Achmatowicz Rearrangement

“…These results were supportive of our proposed formal [3,5]-sigmatropic rearrangement of 1 p/1 q with 1,5allyl shift. When propargyl instead of allyl was attempted for the 1,5-shift, the sequential rearrangements occurred with high efficiency and fidelity to provide the allene 3 p with Angewandte 88 % yield, as supportive of our formal [3,5]-sigmatropic rearrangement. In the course of expanding the substrate scope, we also encountered some challenges, for example, substrate 1 s generated a mixture of products (3 s, 3 s', and 3 s") that might be derived from 1,5-allyl shift, Prins cyclization, and Friedel-Crafts alkylation.…”

“…Careful spectra analysis of the rearranged products 3 p and 3 q (81 % and 82 % yield, respectively) suggested the presence of di-and tri-substituted alkenes (entries 16-17), consistent with C5À C3' bond formation. These results were supportive of our proposed formal [3,5]-sigmatropic rearrangement of 1 p/1 q with 1,5allyl shift. When propargyl instead of allyl was attempted for the 1,5-shift, the sequential rearrangements occurred with high efficiency and fidelity to provide the allene 3 p with Angewandte 88 % yield, as supportive of our formal [3,5]-sigmatropic rearrangement.…”

1,5‐Allyl Shift by a Sequential Achmatowicz/Oxonia‐Cope/Retro‐Achmatowicz Rearrangement

“…These results were supportive of our proposed formal [3,5]-sigmatropic rearrangement of 1 p/1 q with 1,5allyl shift. When propargyl instead of allyl was attempted for the 1,5-shift, the sequential rearrangements occurred with high efficiency and fidelity to provide the allene 3 p with Angewandte 88 % yield, as supportive of our formal [3,5]-sigmatropic rearrangement. In the course of expanding the substrate scope, we also encountered some challenges, for example, substrate 1 s generated a mixture of products (3 s, 3 s', and 3 s") that might be derived from 1,5-allyl shift, Prins cyclization, and Friedel-Crafts alkylation.…”

“…Careful spectra analysis of the rearranged products 3 p and 3 q (81 % and 82 % yield, respectively) suggested the presence of di-and tri-substituted alkenes (entries 16-17), consistent with C5À C3' bond formation. These results were supportive of our proposed formal [3,5]-sigmatropic rearrangement of 1 p/1 q with 1,5allyl shift. When propargyl instead of allyl was attempted for the 1,5-shift, the sequential rearrangements occurred with high efficiency and fidelity to provide the allene 3 p with Angewandte 88 % yield, as supportive of our formal [3,5]-sigmatropic rearrangement.…”

1,5‐Allyl Shift by a Sequential Achmatowicz/Oxonia‐Cope/Retro‐Achmatowicz Rearrangement

“…Careful spectra analysis of the rearranged products 3 p and 3 q (81 % and 82 % yield, respectively) suggested the presence of di-and tri-substituted alkenes (entries 16-17), consistent with C5À C3' bond formation. These results were supportive of our proposed formal [3,5]-sigmatropic rearrangement of 1 p/1 q with 1,5allyl shift. When propargyl instead of allyl was attempted for the 1,5-shift, the sequential rearrangements occurred with high efficiency and fidelity to provide the allene 3 p with…”

“…Chemie Zuschriften 88 % yield, as supportive of our formal [3,5]-sigmatropic rearrangement. In the course of expanding the substrate scope, we also encountered some challenges, for example, substrate 1 s generated a mixture of products (3 s, 3 s', and 3 s") that might be derived from 1,5-allyl shift, Prins cyclization, and Friedel-Crafts alkylation.…”

“…Unexpectedly, we isolated a minor product that was confirmed through careful analysis of NMR data to be a furan-derived compound 3 a (< 10 % yield). While puzzled about the mechanism accounting for this minor product, we recognized that this two-step sequence realized an unprecedented 1,5-allyl shift, which cannot be achieved by Woodward-Hoffmann forbidden [3,5]-sigmatropic rearrangement. Our attempts on direct pericyclic reaction of 1 a under thermal or basic condition failed to effect the similar 1,5-allyl shift (1 a!3a), which further demonstrated the experimental difficulty of [3,5]-sigmatropic rearrangement.…”

1,5‐Allyl Shift by a Sequential Achmatowicz/Oxonia‐Cope/Retro‐Achmatowicz Rearrangement

“…These results were supportive of our proposed formal [3,5]-sigmatropic rearrangement of 1 p/1 q with 1,5allyl shift. When propargyl instead of allyl was attempted for the 1,5-shift, the sequential rearrangements occurred with high efficiency and fidelity to provide the allene 3 p with Angewandte 88 % yield, as supportive of our formal [3,5]-sigmatropic rearrangement. In the course of expanding the substrate scope, we also encountered some challenges, for example, substrate 1 s generated a mixture of products (3 s, 3 s', and 3 s") that might be derived from 1,5-allyl shift, Prins cyclization, and Friedel-Crafts alkylation.…”

“…Careful spectra analysis of the rearranged products 3 p and 3 q (81 % and 82 % yield, respectively) suggested the presence of di-and tri-substituted alkenes (entries 16-17), consistent with C5À C3' bond formation. These results were supportive of our proposed formal [3,5]-sigmatropic rearrangement of 1 p/1 q with 1,5allyl shift. When propargyl instead of allyl was attempted for the 1,5-shift, the sequential rearrangements occurred with high efficiency and fidelity to provide the allene 3 p with Angewandte 88 % yield, as supportive of our formal [3,5]-sigmatropic rearrangement.…”

1,5‐Allyl Shift by a Sequential Achmatowicz/Oxonia‐Cope/Retro‐Achmatowicz Rearrangement

“…Careful spectra analysis of the rearranged products 3 p and 3 q (81 % and 82 % yield, respectively) suggested the presence of di-and tri-substituted alkenes (entries 16-17), consistent with C5À C3' bond formation. These results were supportive of our proposed formal [3,5]-sigmatropic rearrangement of 1 p/1 q with 1,5allyl shift. When propargyl instead of allyl was attempted for the 1,5-shift, the sequential rearrangements occurred with high efficiency and fidelity to provide the allene 3 p with…”

“…Chemie Zuschriften 88 % yield, as supportive of our formal [3,5]-sigmatropic rearrangement. In the course of expanding the substrate scope, we also encountered some challenges, for example, substrate 1 s generated a mixture of products (3 s, 3 s', and 3 s") that might be derived from 1,5-allyl shift, Prins cyclization, and Friedel-Crafts alkylation.…”

“…Unexpectedly, we isolated a minor product that was confirmed through careful analysis of NMR data to be a furan-derived compound 3 a (< 10 % yield). While puzzled about the mechanism accounting for this minor product, we recognized that this two-step sequence realized an unprecedented 1,5-allyl shift, which cannot be achieved by Woodward-Hoffmann forbidden [3,5]-sigmatropic rearrangement. Our attempts on direct pericyclic reaction of 1 a under thermal or basic condition failed to effect the similar 1,5-allyl shift (1 a!3a), which further demonstrated the experimental difficulty of [3,5]-sigmatropic rearrangement.…”

1,5‐Allyl Shift by a Sequential Achmatowicz/Oxonia‐Cope/Retro‐Achmatowicz Rearrangement

“…These results were supportive of our proposed formal [3,5]-sigmatropic rearrangement of 1 p/1 q with 1,5allyl shift. When propargyl instead of allyl was attempted for the 1,5-shift, the sequential rearrangements occurred with high efficiency and fidelity to provide the allene 3 p with Angewandte 88 % yield, as supportive of our formal [3,5]-sigmatropic rearrangement. In the course of expanding the substrate scope, we also encountered some challenges, for example, substrate 1 s generated a mixture of products (3 s, 3 s', and 3 s") that might be derived from 1,5-allyl shift, Prins cyclization, and Friedel-Crafts alkylation.…”

“…Careful spectra analysis of the rearranged products 3 p and 3 q (81 % and 82 % yield, respectively) suggested the presence of di-and tri-substituted alkenes (entries 16-17), consistent with C5À C3' bond formation. These results were supportive of our proposed formal [3,5]-sigmatropic rearrangement of 1 p/1 q with 1,5allyl shift. When propargyl instead of allyl was attempted for the 1,5-shift, the sequential rearrangements occurred with high efficiency and fidelity to provide the allene 3 p with Angewandte 88 % yield, as supportive of our formal [3,5]-sigmatropic rearrangement.…”

1,5‐Allyl Shift by a Sequential Achmatowicz/Oxonia‐Cope/Retro‐Achmatowicz Rearrangement

“…Careful spectra analysis of the rearranged products 3 p and 3 q (81 % and 82 % yield, respectively) suggested the presence of di-and tri-substituted alkenes (entries 16-17), consistent with C5À C3' bond formation. These results were supportive of our proposed formal [3,5]-sigmatropic rearrangement of 1 p/1 q with 1,5allyl shift. When propargyl instead of allyl was attempted for the 1,5-shift, the sequential rearrangements occurred with high efficiency and fidelity to provide the allene 3 p with…”

“…Chemie Zuschriften 88 % yield, as supportive of our formal [3,5]-sigmatropic rearrangement. In the course of expanding the substrate scope, we also encountered some challenges, for example, substrate 1 s generated a mixture of products (3 s, 3 s', and 3 s") that might be derived from 1,5-allyl shift, Prins cyclization, and Friedel-Crafts alkylation.…”

“…Unexpectedly, we isolated a minor product that was confirmed through careful analysis of NMR data to be a furan-derived compound 3 a (< 10 % yield). While puzzled about the mechanism accounting for this minor product, we recognized that this two-step sequence realized an unprecedented 1,5-allyl shift, which cannot be achieved by Woodward-Hoffmann forbidden [3,5]-sigmatropic rearrangement. Our attempts on direct pericyclic reaction of 1 a under thermal or basic condition failed to effect the similar 1,5-allyl shift (1 a!3a), which further demonstrated the experimental difficulty of [3,5]-sigmatropic rearrangement.…”