An enantioselective synthesis of macrocyclic core of (+)-callyspongiolide is described, constituting a formal synthesis of this natural product. The synthetic strategy constructs the 14-membered macrocyclic domain via Yamaguchi esterification followed by a challenging ring-closing metathesis (RCM) to effect the final formation of the macrolactone.

An improved second-generation synthesis of the unnatural amino acid components of the anticancer peptaibol culicinin D has been developed. With a protected glutamic acid derivate as the starting material, the process readily delivered the Fmoc-protected free acid derivatives of AHMOD ((2S)-amino-(6R)-hydroxy-(4S)-methyl-8-oxodecanoic acid) and AMD ((2S)-amino-(4S)-methyldecanoic acid) required to support solid phase peptide synthesis (SPPS) for structure-activity studies of the natural product. The same approach also provides improved access to pipecolic acid derivatives. A novel Wittig reagent for one-carbon homologation of aldehydes, developed during this work, is also reported.

Callyspongiolide, a macrolide natural product with a conjugated diene‐ynic side chain, has garnered significant attention from the synthetic community since its isolation from a sea sponge in 2013. Herein, the approaches that have been applied to this bioactive natural product to date are reviewed. These synthetic endeavors have established the absolute stereochemistry of this molecule and allowed further investigation into its promising caspase‐independent bioactivity, while also contributing to the wider field of macrolide synthesis.

Photomask quality for the next generation processing such as DUV scanner lithography is critical, but there still is many problems. In this situation, we have to find some keys to solve these problems to accommodate the narrow scope of the process margin and the printing bias control on wafer, as well as coarse lithography margins. Currently, the CD uniformity of the patterned Cr, or PSM features including the repaired mask patterns, is about In next generation photomask production, there are some fundamental difficulties to overcome as; Firstly, there is the inherent physical behavior of DUV laser on quartz substrate, and secondly, there are photomask defects that invisible to blue laser inspection, but can still be printed onto the wafer. In order to keep up with photomask product requirements, the next generation inspection systems are being developed with i-line and KrF laser sources. However, issues such as low-level transmission defects and critical line-widths defects have not been solved yet.In partially, the Ga+ implantation defect is one ofthese invisible transmission defects due to the fact that the carried inspection tools use a blue laser (488nm), so it is not be counted as a killing defect for the DUV transmitted types. Although it is captured into a false defect, we have a difficult to classify by ion implantation defect.This paper discusses the process margins of FiB Ga+ ion scanning on the opaque repairing of damaged quartz substrate. It will show the effects of reduced intensity or using the Gas Assisted Etching (GAE) process. And, though it has been solved somewhat, we also have to consider the CD control specifications for the next generation device such as 1G DRAM with DUV lithography. In this experiment, we have evaluated the printability of 4X DUV scanner after both opaque and clear defect repair with a Focused Ion Beam (FIB) system. We also confirmed the accuracy of edge repair, implantation effects of each FIB machine and determined the topography ofrepair by AFM.