@book_section {CaltechAUTHORS_https://authors.library.caltech.edu/id/eprint/99769, title ="Transition‐Metal‐Free Catalytic C─H Bond Silylation", author = "Schuman, David P. and Liu, Wen‐Bo", pages = "213-240", month = "November", year = "2019", doi = "10.1002/9783527814787.ch7", isbn = "9783527344536", url = "https://resolver.caltech.edu/CaltechAUTHORS:20191111-083817296", note = "© 2020 Wiley‐VCH Verlag GmbH & Co. KGaA. \n\nPublished Online: 08 November 2019; Published Print: 11 November 2019.", revision_no = "7", abstract = "Herein, we provide a detailed look at the state of transition‐metal‐free catalytic C–H silylation with select examples to highlight specific advances during the field's recent development. The reactions are categorized by type of catalyst (i.e. Lewis acid, Brønsted acid, Brønsted base, and radical initiation catalysts). For each catalyst system presented, an overview of the substrate scope, mechanism (if known), and significant limitations is discussed.", } @book_section {CaltechAUTHORS_https://authors.library.caltech.edu/id/eprint/94469, title ="Discussion Addendum for: Preparation of (S)-tert-ButylPHOX and (S)-2-Allyl-2-Methylcyclohexanone", author = "Sun, Alexander W. and Stoltz, Brian M.", month = "April", year = "2019", doi = "10.1002/0471264229.os095.29", isbn = "9780471264224", url = "https://resolver.caltech.edu/CaltechAUTHORS:20190404-143251363", note = "© 2019 by Organic Syntheses, Inc. Published by John Wiley and Sons, Inc. \n\nPublished Online: 02 April 2019.", revision_no = "10", abstract = "[no abstract]", } @book_section {CaltechAUTHORS_https://authors.library.caltech.edu/id/eprint/81560, title ="Asymmetric Synthesis of Quaternary Stereocenters via Metal Enolates", author = "Korch, Katerina M. and Loskot, Steven A.", pages = "1-85", month = "January", year = "2016", doi = "10.1002/9780470682531.pat0858", isbn = "9780470682531", url = "https://resolver.caltech.edu/CaltechAUTHORS:20170919-091408635", note = "© 2016 John Wiley & Sons, Ltd. \n\nPublished Online: 15 SEP 2017.", revision_no = "10", abstract = "The strategy of using chiral metal enolate intermediates in a diverse variety of asymmetric transformations has allowed the generation of quaternary stereocenter-bearing products that are otherwise difficult to access. Many classic transformations including aldol, Mannich, conjugate addition, alkylation, and pericyclic-type reactions, as well as allylic alkylation and α-arylation/alkenylation, have been adapted to proceed through chiral metal enolate intermediates, allowing the asymmetric synthesis of many complex products in both an intermolecular and intramolecular manner. These transformations have proven useful in the synthesis of natural products and may also be applied to the synthesis of novel pharmaceuticals and other compounds of interest in the future. This review includes work done up to and including the year 2014.", } @book_section {CaltechAUTHORS_https://authors.library.caltech.edu/id/eprint/54062, title ="Alkylations of Enols and Enolates", author = "Stoltz, B. M. and Bennett, N. B.", volume = "3", pages = "1-55", month = "January", year = "2014", doi = "10.1016/B978-0-08-097742-3.00301-3", isbn = "978-0-08-097743-0", url = "https://resolver.caltech.edu/CaltechAUTHORS:20150126-091231023", note = "© 2014 Elsevier Ltd.", revision_no = "12", abstract = "Enolate alkylation, the nucleophilic substitution of electrophilic alkylating reagents by carbon nucleophiles generated from the adeprotonation\nof carbonyl compounds, is one among the most fundamental and important methods for the construction of\ncarbon–carbon bonds adjacent to a carbonyl group. Over the past fifty years, this methodology has evolved into a highly selective,\nefficient, and essential technique integral to the practitioners of pharmaceutical industry, chemical biology, and academic organic\nsynthesis.\nSince the previous publication of Comprehensive Organic Synthesis in 1991, a field-wide explosion of interest in catalysis has\nsparked the development of numerous metal and metal-free catalytic alkylation methods. These advances have introduced new\nmethods for enolate formation, expanded substrate scope, and enabled highly stereoselective α-alkylations. New techniques allow\nelaboration of a diverse array of small molecules and have made enolate alkylation one of the most important methods for\nasymmetric carbon–carbon bond formation.\nOwing to the overwhelming wealth of literature on carbonyl chemistry, attempt has been made to narrowly define ‘enolate\nalkylation’ to encompass only the reactions of enolates with sp^3-hybridized carbon electrophiles. Aldol reactions, conjugate\nadditions, arylations, and functionalizations of enamines and metalloenamines will be addressed in other chapters of this\ncompendium.", } @book_section {CaltechAUTHORS_https://authors.library.caltech.edu/id/eprint/37952, title ="Catalytic Enantioselective Alkylation of Prochiral Ketone Enolates", author = "Reeves, Corey M. and Stoltz, Brian M.", pages = "1-10", month = "November", year = "2012", doi = "10.1002/9783527652235.ch1", isbn = "9783527329212", url = "https://resolver.caltech.edu/CaltechAUTHORS:20130415-152954275", note = "© 2012 Wiley-VCH Verlag GmbH & Co. KGaA.\nPublished 2012 by Wiley-VCH Verlag GmbH & Co. KGaA.\n\nPublished Online: 14 Jan 2013; Published Print: 14 Nov 2012", revision_no = "17", abstract = "The synthesis of stereogenic all-carbon quaternary centers remains a formidable\nchallenge, notwithstanding the strides made by modem organic chemistry in this\nregard. Contemporary advances in enolate alkylation have made it a fundamental\nstrategy for the construction of C-C bonds. Although methods for the reaction\nof a number of enolate types (e.g., ester, ketone, and propionimide) with a variety of\nalkylating agents exist, catalytic enantioselective variants of these transformations\nare relatively rare. Of the catalytic asymmetric methods available, there have been\nfew examples of general techniques for the asymmetric alkylation of carbocyclic\nsystems and still fewer examples that have the capacity to deliver all-carbon\nquaternary stereocenters. While the Merck phase transfer methylation and Koga\nalkylation of 2-alkyltetralone-derived silyl enol ethers represent notable exceptions, the breadth of application and utility of these reactions bas been limited. In fact,\nat the outset of our investigations in this area, there were no examples of catalytic\nenantioselective alkylations of monocyclic 2-substituted cycloalkanone enolates in\nthe absence of either α'-blocking groups or α-enolate-stabilizing groups (e.g., R =\naryl, ester, etc.; Figure 1). Concurrent to our work in this area, Trost and coworkers have published a series of papers that complement our studies. Jacobsen and\ncoworkers, as well, have revealed a unique enantioselective method involving the\nchromium-catalyzed reaction of tin enolates with a variety of unactivated alkyl\nhalides . Herein, we relate our development of Pd-catalyzed enantioselective\nfunctionalization reactions of prochiral enolates, specifically tetrasubstituted cyclic\nketone enolates that give rise to quaternary stereogenicity. The synthetic utility\nof the building blocks derived from these reactions is demonstrated by application\nin a number of total syntheses.", } @book_section {CaltechAUTHORS_https://authors.library.caltech.edu/id/eprint/38547, title ="Natural Products as Inspiration for Reaction Development: Catalytic Enantioselective Decarboxylative Reactions of Prochiral Enolate Equivalents", author = "Behenna, Douglas C. and Stoltz, Brian M.", number = "44", pages = "281-314", month = "August", year = "2012", doi = "10.1007/3418_2012_49", isbn = "978-3-642-34285-1", url = "https://resolver.caltech.edu/CaltechAUTHORS:20130516-140126410", note = "© 2013 Springer-Verlag Berlin Heidelberg.\n\nPublished online: 18 August 2012.\n", revision_no = "19", abstract = "This account describes the circumstances leading to our group's\ninnovations in the area of decarboxylative asymmetric allylic alkylation reactions\nand the initial discovery of palladium phosphinooxazoline complexes as efficient\nenantioselective catalysts. This chapter also chronicles the growth of the methodology\nto include several substrate classes, the expansion of the project into several other\nreaction manifolds, and the use of these reactions in natural product synthesis. Finally,\nimportant contributions from other research groups involving related methods or\nproducts similar to the α-quaternary products that are the focus of our studies, as\nwell as future directions for asymmetric alkylation reactions, are discussed.", }