Correction: Enantioselective synthesis of isochromans and tetrahydroisoquinolines by C-H insertion of donor/donor carbenes.

[This corrects the article DOI: 10.1039/C9SC05111B.].

Enantioselective synthesis of isochromans and tetrahydroisoquinolines by C-H insertion of donor/donor carbenes.

Reports of C-H insertions forming six-membered rings containing heteroatoms are rare due to Stevens rearrangements occurring after nucleophilic attack on the carbene by a heteroatom. Using donor/donor carbenes and Rh(-PTAD) as a catalyst, we have synthesized a collection of isochroman substrates in good yield, with excellent diastereo- and enantioselectivity, and no rearrangement products were observed. Furthermore, we report the first synthesis of six-membered rings containing nitrogen by C-H insertion to form tetrahydroisoquinolines.

Transition Metal Catalyzed Insertion Reactions with Donor/Donor Carbenes.

Donor/donor carbenes are relatively new in the field of carbene chemistry; although applications in C-H and X-H insertion reactions are few in number, they demonstrate exquisite chemo- and stereo-selectivity. Recent reports have shown that C-H, N-H, B-H, O-H, S-H, Si-H, Ge-H, Sn-H and P-H insertion reactions are feasible with a variety of transition metal catalysts, both inter- and intramolecularly. Furthermore, high degrees of diastereo- and enantioselectivity have been observed in several cases.

Au(I)-Catalyzed Synthesis of Trisubstituted Indolizines from 2-Propargyloxypyridines and Methyl Ketones.

A new Au(I)-catalyzed method for the preparation of trisubstituted indolizines from easily accessible 2-propargyloxy-pyridines is reported. The reaction tolerates a wide range of functionality, allowing for diversity to be introduced in four distinct regions of the product (R, R, R, and Ar). The proposed mechanism proceeds via enol addition to an allenamide intermediate and explains the observed increase in yields when electron poor methyl ketones are utilized.

Enantioselective Synthesis of Indolines, Benzodihydrothiophenes, and Indanes by C-H Insertion of Donor/Donor Carbenes.

We employ a single catalyst/oxidant system to enable the asymmetric syntheses of indolines, benzodihydrothiophenes, and indanes by C-H insertion of donor/donor carbenes. This methodology enables the rapid construction of densely substituted five-membered rings that form the core of many drug targets and natural products. Furthermore, oxidation of hydrazones to the corresponding diazo compounds proceeds in situ, enabling a relatively facile one- or two-pot protocol in which isolation of potentially explosive diazo alkanes is avoided.

Asymmetric Synthesis of Homocitric Acid Lactone.

A short, diastereoselective synthesis of homocitric acid lactone is described. The key step is a bioinspired aldol addition to set the stereogenic center in an intermediate that requires only modest oxidation state manipulation to complete the synthesis. This approach enables rapid generation of isotopomers in which carbon and hydrogen can be replaced by heavier nuclei at nearly every position.