Modal and Polarization Qubits in Ti:LiNbO3_3 Photonic Circuits for a Universal Quantum Logic Gate

Lithium niobate photonic circuits have the salutary property of permitting the generation, transmission, and processing of photons to be accommodated on a single chip. Compact photonic circuits such as these, with multiple components integrated on a single chip, are crucial for efficiently implementing quantum information processing schemes. We present a set of basic transformations that are useful for manipulating modal qubits in Ti:LiNbO$_3$ photonic quantum circuits. These include the mode analyzer, a device that separates the even and odd components of a state into two separate spatial paths; the mode rotator, which rotates the state by an angle in mode space; and modal Pauli spin operators that effect related operations. We also describe the design of a deterministic, two-qubit, single-photon, CNOT gate, a key element in certain sets of universal quantum logic gates. It is implemented as a Ti:LiNbO$_3$ photonic quantum circuit in which the polarization and mode number of a single photon serve as the control and target qubits, respectively. It is shown that the effects of dispersion in the CNOT circuit can be mitigated by augmenting it with an additional path. The performance of all of these components are confirmed by numerical simulations. The implementation of these transformations relies on selective and controllable power coupling among single- and two-mode waveguides, as well as the polarization sensitivity of the Pockels coefficients in LiNbO$_3$

Hydrophosphination of Bicyclo[1.1.0]butane-1-carbonitriles

Hydrophosphination of bicyclo[1.1.0]­butyl nitriles with phosphine boranes and phosphites provided novel cyclobutyl-P derivatives. The reaction generally favors the <i>syn</i>-diastereomer, and the nitrile can be reduced and converted to other functional groups, thus enabling the preparation of bidentate ligands that access new conformational space by virtue of their attachment to the torsionally malleable but sterically restrictive cyclobutane scaffold. The enantioselective hydrogenation of dehydrophenylalanine using a bidentate phosphine–phosphite ligand illustrates the synthetic utility of the newly prepared scaffold

Atom-Economical Cross-Coupling of Internal and Terminal Alkynes to Access 1,3-Enynes

Selective carbon–carbon (C–C) bond formation in chemical synthesis generally requires pre-functionalized building blocks. However, the requisite pre-functionalization steps undermine the efficiency of multi-step synthetic sequences, which is particularly problematic in large-scale applications, such as in the commercial production of pharmaceuticals. Herein, we describe a selective and catalytic method for synthesizing 1,3-enynes without pre-functionalized building blocks. This method is facilitated by a tailored P,N-ligand that enables regioselective coupling and suppresses secondary E/Z-isomerization of the product. The transformation enables several classes of unactivated internal acceptor alkynes to be coupled with terminal donor alkynes to deliver 1,3-enynes in a highly regio- and stereoselective manner. The scope of compatible acceptor alkynes includes propargyl alcohols, (homo)propargyl amine derivatives, and (homo)propargyl carboxamides. The reaction is scalable and can operate effectively with 0.5 mol% catalyst loading. The products are versatile intermediates that can participate in various downstream transformations. We also present preliminary mechanistic experiments that are consistent with a redox-neutral Pd(II) catalytic cycle

Carbamoyl Anion Addition to Nitrones

The addition of carbamoyl anions derived from <i>N</i>,<i>N</i>-disubstituted formamides and LDA to <i>N</i>-<i>tert</i>-butyl nitrones is described. The reaction was demonstrated with a variety of formamides and nitrones and provided a direct route to α-(<i>N</i>-hydroxy)­amino amides. The use of a <i>tert</i>-leucinol derived chiral auxiliary on the nitrone provided products in good diastereoselectivity. Derivatization of the products by <i>tert</i>-butyl deprotection or <i>N</i>-deoxygenation was demonstrated

The Reaction of Grignard Reagents with Bunte Salts: A Thiol-Free Synthesis of Sulfides

S-Alkyl, S-aryl, and S-vinyl thiosulfate sodium salts (Bunte salts) react with Grignard reagents to give sulfides in good yields. The S-alkyl Bunte salts are prepared from odorless sodium thiosulfate by an S_N2 reaction with alkyl halides. A Cu-catalyzed coupling of sodium thiosulfate with aryl and vinyl halides was developed to access S-aryl and S-vinyl Bunte salts. The reaction is amenable to a broad structural array of Bunte salts and Grignard reagents. Importantly, this route to sulfides avoids the use of malodorous thiol starting materials or byproducts

Part 2: Designation and Justification of API Starting Materials: Current Practices across Member Companies of the IQ Consortium

Designation and justification of active pharmaceutical ingredient starting material (API SM) is a standard part of the drug development and commercialization process. However, knowledge of current practices used within the industry varies, depending on the individual company interpretation of regulatory guidelines. In 2011, the API and Analytical Leadership Groups within the International Consortium for Innovation and Quality in Pharmaceutical Development (IQ Consortium or IQ), established a Working Group on API SMs to determine current practices within the pharmaceutical industry on this topic. A survey composed of four key areas, representing (1) drug substance (DS) attributes, (2) API SM attributes, (3) control strategy, and (4) regulatory practices and strategy, was developed and distributed to IQ member companies. Data representing a total of 50 API SMs (used to prepare 24 late stage clinical or marketed DSs) were obtained. This data was used to gain a better understanding of approaches utilized by pharmaceutical companies to define API SMs. The data gathered was anonymous, and the key information obtained is summarized in this manuscript. While no single approach to justifying API SMs emerged from the survey data, key trends were evident that will provide valuable insight for the reader on this important topic